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JSP、EL、JSTL

目录

8.1 概念：

Java Server Pages： java服务器端页面

可以理解为：一个特殊的页面，其中既可以指定定义html标签，又可以定义java代码

用于简化书写！！！

8.2 原理

SP本质上就是一个Servlet3.

8.3 JSP的脚本

JSP定义Java代码的方式

<% 代码 %>：定义的java代码，在service方法中。service方法中可以定义什么，该脚本中就可以定义什么。

<%! 代码 %>：定义的java代码，在jsp转换后的java类的成员位置。

<%= 代码 %>：定义的java代码，会输出到页面上。输出语句中可以定义什么，该脚本中就可以定义什么。

8.4 JSP的内置对象：

在jsp页面中不需要获取和创建，可以直接使用的对象

jsp一共有9个内置对象。

request

response

out：字符输出流对象

可以将数据输出到页面上。和response.getWriter()类似

response.getWriter()和out.write()的区别：

在tomcat服务器真正给客户端做出响应之前，会先找response缓冲区数据，再找out缓冲区数据。 response.getWriter()数据输出永远在out.write()之前

8.5 案例:改造Cookie案例

<%@ page import="java.util.Date" %>
<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.net.URLDecoder" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>itcast</title>
</head>
<body>

<%

    //1.获取所有Cookie
    Cookie[] cookies = request.getCookies();
    boolean flag = false;//没有cookie为lastTime
    //2.遍历cookie数组
    if(cookies != null && cookies.length > 0){
        for (Cookie cookie : cookies) {
            //3.获取cookie的名称
            String name = cookie.getName();
            //4.判断名称是否是：lastTime
            if("lastTime".equals(name)){
                //有该Cookie，不是第一次访问

                flag = true;//有lastTime的cookie

                //设置Cookie的value
                //获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
                Date date  = new Date();
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
                String str_date = sdf.format(date);
                System.out.println("编码前："+str_date);
                //URL编码
                str_date = URLEncoder.encode(str_date,"utf-8");
                System.out.println("编码后："+str_date);
                cookie.setValue(str_date);
                //设置cookie的存活时间
                cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
                response.addCookie(cookie);


                //响应数据
                //获取Cookie的value，时间
                String value = cookie.getValue();
                System.out.println("解码前："+value);
                //URL解码：
                value = URLDecoder.decode(value,"utf-8");
                System.out.println("解码后："+value);
                %>
            <h1>欢迎回来，您上次访问时间为:<%=value%></h1>
            <input>

<%



                break;

            }
        }
    }


    if(cookies == null || cookies.length == 0 || flag == false){
        //没有，第一次访问

        //设置Cookie的value
        //获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
        Date date  = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
        String str_date = sdf.format(date);
        System.out.println("编码前："+str_date);
        //URL编码
        str_date = URLEncoder.encode(str_date,"utf-8");
        System.out.println("编码后："+str_date);

        Cookie cookie = new Cookie("lastTime",str_date);
        //设置cookie的存活时间
        cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
        response.addCookie(cookie);

%>

        <h1>您好，欢迎您首次访问</h1>
<span></span>

<%
    }

%>

<input>




</body>
</html>

8.6 指令

  • 作用：用于配置JSP页面，导入资源文件

  • 格式：

    <%@ 指令名称 属性名1=属性值1 属性名2=属性值2 ... %>

  • 分类：

    1. page： 配置JSP页面的

      • contentType：等同于response.setContentType()
        1. 设置响应体的mime类型以及字符集
        2. 设置当前jsp页面的编码（只能是高级的IDE才能生效，如果使用低级工具，则需要设置pageEncoding属性设置当前页面的字符集）
      • import：导包
      • errorPage：当前页面发生异常后，会自动跳转到指定的错误页面
      • isErrorPage：标识当前也是是否是错误页面。
        • true：是，可以使用内置对象exception
        • false：否。默认值。不可以使用内置对象exception

    2. include ： 页面包含的。导入页面的资源文件

      <%@include file="top.jsp"%>
  1. taglib ： 导入资源
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

prefix：前缀，自定义的

8.7 注释:

  1. html注释： :只能注释html代码片段
  2. jsp注释：推荐使用
    <%-- --%>：可以注释所有

8.8 内置对象

在jsp页面中不需要创建，直接使用的对象

变量名真实类型作用
pageContextPageContext当前页面共享数据，还可以获取其他八个内置对象
requestHttpServletRequest一次请求访问的多个资源(转发)
sessionHttpSession一次会话的多个请求间
applicationServletContext所有用户间共享数据
responseHttpServletResponse响应对象
pageObject当前页面(Servlet)的对象 this
outJspWriter输出对象，数据输出到页面上
configServletConfigServlet的配置对象
exceptionThrowable异常对象

8.9 MVC：开发模式

8.9.1 jsp演变历史

  1. 早期只有servlet，只能使用response输出标签数据，非常麻烦
  2. 后来又jsp，简化了Servlet的开发，如果过度使用jsp，在jsp中即写大量的java代码，有写html表，造成难于维护，难于分工协作
  3. 再后来，java的web开发，借鉴mvc开发模式，使得程序的设计更加合理性

8.9.2 MVC：

  1. M：Model，模型。JavaBean
    • 完成具体的业务操作，如：查询数据库，封装对象
  2. V：View，视图。JSP
    • 展示数据
  3. C：Controller，控制器。Servlet
    • 获取用户的输入
    • 调用模型
    • 将数据交给视图进行展示

8.9.3 MVC优缺点：

  1. 优点：

  • 耦合性低，方便维护，可以利于分工协作

  • 重用性高

  1. 缺点：
  • 使得项目架构变得复杂，对开发人员要求高

8.10 EL表达式

8.10.1 概述

  1. 概念：Expression Language 表达式语言
  2. 作用：替换和简化jsp页面中java代码的编写
  3. 语法：${表达式}
  4. 注意：
    • jsp默认支持el表达式的。如果要忽略el表达式
      1. 设置jsp中page指令中：isELIgnored=“true” 忽略当前jsp页面中所有的el表达式
      2. \ ${表达式} ：忽略当前这个el表达式

8.10.2 使用

运算：

  • 运算符：
    1. 算数运算符： + - * /(div) %(mod)
    2. 比较运算符： > < >= <= == !=
    3. 逻辑运算符： &&(and) ||(or) !(not)
    4. 空运算符： empty
      • 功能：用于判断字符串、集合、数组对象是否为null或者长度是否为0
      • ${empty list}:判断字符串、集合、数组对象是否为null或者长度为0
      • ${not empty str}:表示判断字符串、集合、数组对象是否不为null 并且 长度>0

获取值

  1. el表达式只能从域对象中获取值
  2. 语法：

  • ${域名称.键名}：从指定域中获取指定键的值

    • 域名称：
      • pageScope --> pageContext
      • requestScope --> request
      • sessionScope --> session
      • applicationScope --> application（ServletContext）
    • 举例：在request域中存储了name=张三
    • 获取：${requestScope.name}

  • ${键名}：表示依次从最小的域中查找是否有该键对应的值，直到找到为止。

  • 获取对象、List集合、Map集合的值

    • 对象：${域名称.键名.属性名}

      • 本质上会去调用对象的getter方法

         <%
        User user=new User("张三",34,new Date());
        request.setAttribute("u",user);
    %>

    <h1>el获取对象的值</h1>
    ${requestScope.u}<br>
    ${requestScope.u.name}<br>
    ${u.age}<br>
    ${u.birthday}<br>

      • List集合：${域名称.键名[索引]}

      • Map集合：

        ${域名称.键名.key名称}
${域名称.键名["key名称"]}

​

  1. 隐式对象：

    el表达式中有11个隐式对象

    ​ pageContext：

    ​ 获取jsp其他八个内置对象

    ​ ${pageContext.request.contextPath}：动态获取虚拟目录

​

8.11 JSTL

8.11.1 概述

概念：JavaServer Pages Tag Library

JSP标准标签库

是由Apache组织提供的开源的免费的jsp标签

作用：用于简化和替换jsp页面上的java代码

8.11.2 使用步骤：

导入jstl相关jar包

引入标签库：taglib指令： <%@ taglib %>

使用标签

8.11.3 常用的JSTL标签

if:相当于java代码的if语句

属性：

test 必须属性，接受boolean表达式

如果表达式为true，则显示if标签体内容，如果为false，则不显示标签体内容

一般情况下，test属性值会结合el表达式一起使用

注意： c:if标签没有else情况，想要else情况，则可以在定义一个c:if标签

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 19:04
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>c:if</title>
</head>
<body>
    <c:if test="true">
        我是真。。。。
    </c:if>

    <%
        int a=6;
    %>

    <c:if test="${number % 2 == 0}">
        是偶数。。。。
    </c:if>
</body>
</html>

choose:相当于java代码的switch语句

相当于switch声明

使用when标签做判断 ，相当于case

使用otherwise标签做其他情况的声明 ，相当于default 、

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 19:12
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>c:choose</title>
</head>
<body>
    <%
        request.setAttribute("number",5);
    %>
    <c:choose>
        <c:when test="${number==1}">周一</c:when>
        <c:when test="${number==2}">周二</c:when>
        <c:when test="${number==3}">周三</c:when>
        <c:when test="${number==4}">周四</c:when>
        <c:when test="${number==5}">周五</c:when>
        <c:when test="${number==6}">周六</c:when>
        <c:when test="${number==7}">周七</c:when>
        <c:otherwise>您输入的有误!!!</c:otherwise>
    </c:choose>
</body>
</html>

foreach:相当于java代码的for语句

  1. 完成重复的操作
    for(int i = 0; i < 10; i ++){

    }

    属性：

    begin：开始值

    end：结束值

    var：临时变量

    step：步长

    varStatus：循环状态对象

  2. 遍历容器
    List< User> list;
    for(User user : list){

    }

    属性：
    items:容器对象
    var:容器中元素的临时变量
    varStatus:循环状态对象
    index:容器中元素的索引，从0开始
    count:循环次数，从1开始

<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.List" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
    <title>foreach标签</title>
</head>
<body>


<c:forEach begin="1" end="10" var="i" step="2" varStatus="s">
    ${i} <h3>${s.index}<h3> <h4> ${s.count} </h4><br>

</c:forEach>

    <hr>


    <%
        List list = new ArrayList();
        list.add("aaa");
        list.add("bbb");
        list.add("ccc");

        request.setAttribute("list",list);


    %>

    <c:forEach items="${list}" var="str" varStatus="s">

            ${s.index} ${s.count} ${str}<br>

    </c:forEach>


</body>
</html>

练习

需求：在request域中有一个存有User对象的List集合。需要使用jstl+el将list集合数据展示到jsp页面的表格table中

package itcast.pojo;

import java.util.Date;

public class User {
    private  String name;
    private  int age;
    private Date birthday;

    public User(String name, int age, Date birthday) {
        this.name = name;
        this.age = age;
        this.birthday = birthday;
    }

    public User() {

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", birthday=" + birthday +
                '}';
    }
}


<%@ page import="cn.itcast.domain.User" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.Date" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
    <title>test</title>
</head>
<body>

<%

    List list = new ArrayList();
    list.add(new User("张三",23,new Date()));
    list.add(new User("李四",24,new Date()));
    list.add(new User("王五",25,new Date()));

    request.setAttribute("list",list);


%>

<table  width="500" align="center">
    <tr>
        <th>编号</th>
        <th>姓名</th>
        <th>年龄</th>
        <th>生日</th>
    </tr>
    <%--数据行--%>
    <c:forEach items="${list}" var="user" varStatus="s">

        <c:if test="${s.count % 2 != 0}">

            <tr bgcolor="red">
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.age}</td>
                <td>${user.birStr}</td>
            </tr>
        </c:if>

        <c:if test="${s.count % 2 == 0}">

            <tr  bgcolor="green">
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.age}</td>
                <td>${user.birStr}</td>
            </tr>
        // </c:if>
    </c:forEach>

</table>






</body>
</html>

8.12 三层架构：软件设计架构

界面层(表示层web)：用户看的得界面。用户可以通过界面上的组件和服务器进行交互

业务逻辑层service：处理业务逻辑的。

数据访问层dao：操作数据存储文件。

8.12.1案例：用户信息列表展示

  1. 需求：用户信息的增删改查操作

  2. 设计：

    • 技术选型：Servlet+JSP+MySQL+JDBCTempleat+Duird+BeanUtilS+tomcat

    • 数据库设计：

  3. 开发：

  • 环境搭建
  • 创建数据库环境
  • 创建项目，导入需要的jar包
  • 编码
  1. 测试
  2. 部署运维

1 环境搭建

创建数据库，添加数据
create database day17; -- 创建数据库		
use day17; 			   -- 使用数据库		
create table user(   -- 创建表			
	id int primary key auto_increment,			
	name varchar(20) not null,			
	gender varchar(5),			
	age int,			
	address varchar(32),			
	qq	varchar(20),			
	email varchar(50)		
);

INSERT INTO `user` VALUES (1, '张三', '男', 23, '河北省', '2623222222', '[email protected]');
INSERT INTO `user` VALUES (2, '李四', '男', 33, '河南省', '2625555555', '[email protected]');
INSERT INTO `user` VALUES (3, '王五', '女', 27, '重庆', '4522222268', '[email protected]');
INSERT INTO `user` VALUES (4, '柳六', '男', 13, '陕西', '12345', '[email protected]');
INSERT INTO `user` VALUES (5, '钱七', '女', 15, '北京', '88888', '[email protected]');
导入相关jar包

导入静态资源

导入druid.properties文件
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///javawebs
username=root
password=root
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大等待时间
maxWait=3000

2 列表查询

User
package cn.gtt.pojo;

public class User {
    private int id;
    private  String name;
    private  String genter;
    private int age;
    private  String address;
    private  String qq;
    private String email;

    public User(int id, String name, String genter, int age, String address, String qq, String email) {
        this.id = id;
        this.name = name;
        this.genter = genter;
        this.age = age;
        this.address = address;
        this.qq = qq;
        this.email = email;
    }

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGenter() {
        return genter;
    }

    public void setGenter(String genter) {
        this.genter = genter;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getQq() {
        return qq;
    }

    public void setQq(String qq) {
        this.qq = qq;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", genter='" + genter + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                ", qq='" + qq + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}
UserDao
package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();
}
UserDaoImpl
package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }
}
UserService
package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();
}
UserServiceImpl
package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }
}
JDBCUtils
package cn.gtt.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * Druid连接池的工具类
 */
public class JDBCUtils {
//    定义成员变量DataSource
    private static DataSource dataSource;
    
    static {
        try {
//          加载配置文件
            Properties properties = new Properties();
            properties.load(JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"));
//            获取DataSource
            dataSource= DruidDataSourceFactory.createDataSource(properties);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取连接
     */
    public  static Connection getConnection() throws SQLException {
        return  dataSource.getConnection();
    }

    /**
     * 释放资源
     */
    public  static  void  close(ResultSet resultSet,Statement statement, Connection connection){
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(statement!=null){
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }

    /**
     * 获取连接池方法
     */

    public  static  DataSource getDataSource(){
        return  dataSource;
    }




}
UserListServlet
package cn.gtt.web.servlet;


import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/userListServlet")
public class UserListServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        调用UserService完成查询
        UserService userService = new UserServiceImpl();
        List<User> users = userService.findAll();
//        将list存入request域
        req.setAttribute("users",users);
//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);
    }
}
index.jsp
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 20:37
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>
<div align="center">
  <a
<%--          ${pageContext.request.contextPath}来表示请求路径--%>
          href="${pageContext.request.contextPath}/userListServlet" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>
</body>
</html>
list.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

        <tr>
            <td colspan="8" align="center"><a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a></td>
        </tr>
    </table>
</div>
</body>
</html>

3 页面调整

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >1</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >2</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >3</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >4</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >5</a></li>
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

4 登录功能

验证码问题

login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!DOCTYPE html>
<html >
<head>
    <meta charset="utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1"/>
    <title>管理员登录</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <script type="text/javascript">
        //切换验证码
        function refreshCode(){
            //1.获取验证码图片对象
            var vcode = document.getElementById("vcode");

            //2.设置其src属性，加时间戳
            vcode.src = "${pageContext.request.contextPath}/checkCodeServlet?time="+new Date().getTime();
        }
    </script>
</head>
<body>
<div class="container" style="width: 400px;">
    <h3 style="text-align: center;">管理员登录</h3>
    <form action="${pageContext.request.contextPath}/loginServlet" method="post">
        <div class="form-group">
            <label for="user">用户名：</label>
            <input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
        </div>

        <div class="form-group">
            <label for="password">密码：</label>
            <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
        </div>

        <div class="form-inline">
            <label for="vcode">验证码：</label>
            <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
            <a href="javascript:refreshCode();" target="_blank" rel="external nofollow" >
                <img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清点击刷新" id="vcode"/>
            </a>
        </div>
        <hr/>
        <div class="form-group" style="text-align: center;">
            <input class="btn btn btn-primary" type="submit" value="登录">
        </div>
    </form>

    <!-- 出错显示的信息框 -->
    <div class="alert alert-warning alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert" >
            <span>&times;</span>
        </button>
        <strong>${login_msg}</strong>
    </div>
</div>
</body>
</html>

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 20:37
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>
<div align="center">
  <a
<%--          ${pageContext.request.contextPath}来表示请求路径--%>
          href="${pageContext.request.contextPath}/userListServlet" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>
</body>
</html>

User

package cn.gtt.pojo;

public class User {
    private int id;
    private  String name;
    private  String gender;
    private int age;
    private  String address;
    private  String qq;
    private String email;

    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public User(int id, String name, String gender, int age, String address, String qq, String email) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.address = address;
        this.qq = qq;
        this.email = email;
    }

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getQq() {
        return qq;
    }

    public void setQq(String qq) {
        this.qq = qq;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                ", qq='" + qq + '\'' +
                ", email='" + email + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }
}

LoginServlet

package cn.gtt.web.servlet;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.设置编码格式
        req.setCharacterEncoding("utf-8");

//        2.获取数据
//        2.1 获取用户填写验证码
        String verifycode = req.getParameter("verifycode");
//        3.验证码校验
        HttpSession session = req.getSession();
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
//        确保验证码一次性
        session.removeAttribute("CHECKCODE_SERVER");


        if (!checkcode_server.equalsIgnoreCase(verifycode)){
//            验证码不正确
//            提示信息
            req.setAttribute("login_msg","验证码错误！！！");
//            转跳登录页面
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
            return;
        }
//        4.封装user对象
        Map<String, String[]> parameterMap = req.getParameterMap();
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

//        5.调用service查询
        UserService userService = new UserServiceImpl();
        User login = userService.login(user);
//        6.判断是否登录成功
        if (login!=null){
//            将用户存入session
            session.setAttribute("user",login);
//            跳转页面
            resp.sendRedirect(req.getContextPath()+"/index.jsp");
        }else{
//            提示信息
            req.setAttribute("login_msg","用户名或密码错误！！！");
//            转跳登录页面
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
        }


    }
}

5 添加功能

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

add.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!-- HTML5文档-->
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>添加用户</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
    <center><h3>添加联系人页面</h3></center>
    <form action="${pageContext.request.contextPath}/addUserServlet" method="post">
        <div class="form-group">
            <label for="name">姓名：</label>
            <input type="text" class="form-control" id="name" name="name" placeholder="请输入姓名">
        </div>

        <div class="form-group">
            <label>性别：</label>
            <input type="radio" name="gender" value="男" checked="checked"/>男
            <input type="radio" name="gender" value="女"/>女
        </div>

        <div class="form-group">
            <label for="age">年龄：</label>
            <input type="text" class="form-control" id="age" name="age" placeholder="请输入年龄">
        </div>

        <div class="form-group">
            <label for="address">籍贯：</label>
            <select name="address" class="form-control" id="address">
                <option value="陕西">陕西</option>
                <option value="北京">北京</option>
                <option value="上海">上海</option>
            </select>
        </div>

        <div class="form-group">
            <label for="qq">QQ：</label>
            <input type="text" class="form-control" id="qq" name="qq" placeholder="请输入QQ号码"/>
        </div>

        <div class="form-group">
            <label for="email">Email：</label>
            <input type="text" class="form-control" id="email" name="email" placeholder="请输入邮箱地址"/>
        </div>

        <div class="form-group" style="text-align: center">
            <input class="btn btn-primary" type="submit" value="提交" />
            <input class="btn btn-default" type="reset" value="重置" />
            <input class="btn btn-default" type="button" value="返回" />
        </div>
    </form>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }
}

AddUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.设置编码格式
        req.setCharacterEncoding("utf-8");
        
//        获取参数
        Map<String, String[]> parameterMap = req.getParameterMap();

//        封装对象
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

//        调用service保存
        UserService userService=new UserServiceImpl();
        userService.addUser(user);

//        转跳到userListServlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }
}

6 删除

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td>
                    <a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
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            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    public  void  deleteUser(int id);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }
}

DelUserServlet

package cn.gtt.web.servlet;

import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取id
        String id = req.getParameter("id");
//        调用service层删除
        UserService userService=new UserServiceImpl();
        userService.deleteUser(id);
//        转跳到查询所有servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");




    }
}

7 修改

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td>
                    <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

update.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
    <head>
        <!-- 指定字符集 -->
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>修改用户</title>

        <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
        <script src="js/jquery-2.1.0.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        
    </head>
    <body>
        <div class="container" style="width: 400px;">
        <h3 style="text-align: center;">修改联系人</h3>
        <form action="${pageContext.request.contextPath}/updateUserServlet" method="post">
            <!--  隐藏域 提交id-->
            <input type="hidden" name="id" value="${user.id}">

          <div class="form-group">
            <label for="name">姓名：</label>
            <input type="text" class="form-control" id="name" name="name"  value="${user.name}" readonly="readonly" placeholder="请输入姓名" />
          </div>

          <div class="form-group">
            <label>性别：</label>
              <c:if test="${user.gender == '男'}">
                  <input type="radio" name="gender" value="男" checked />男
                  <input type="radio" name="gender" value="女"  />女
              </c:if>

              <c:if test="${user.gender == '女'}">
                  <input type="radio" name="gender" value="男"  />男
                  <input type="radio" name="gender" value="女" checked  />女
              </c:if>


          </div>

          <div class="form-group">
            <label for="age">年龄：</label>
            <input type="text" class="form-control" value="${user.age}" id="age"  name="age" placeholder="请输入年龄" />
          </div>

          <div class="form-group">
            <label for="address">籍贯：</label>
             <select name="address" id="address" class="form-control" >
                 <c:if test="${user.address == '陕西'}">
                    <option value="陕西" selected>陕西</option>
                    <option value="北京">北京</option>
                    <option value="上海">上海</option>
                 </c:if>

                 <c:if test="${user.address == '北京'}">
                     <option value="陕西" >陕西</option>
                     <option value="北京" selected>北京</option>
                     <option value="上海">上海</option>
                 </c:if>

                 <c:if test="${user.address == '上海'}">
                     <option value="陕西" >陕西</option>
                     <option value="北京">北京</option>
                     <option value="上海" selected>上海</option>
                 </c:if>
            </select>
          </div>

          <div class="form-group">
            <label for="qq">QQ：</label>
            <input type="text" id="qq" class="form-control" value="${user.qq}" name="qq" placeholder="请输入QQ号码"/>
          </div>

          <div class="form-group">
            <label for="email">Email：</label>
            <input type="text" id="email" class="form-control" value="${user.email}" name="email" placeholder="请输入邮箱地址"/>
          </div>

             <div class="form-group" style="text-align: center">
                <input class="btn btn-primary" type="submit" value="提交" />
                <input class="btn btn-default" type="reset" value="重置" />
                <input class="btn btn-default" type="button" value="返回"/>
             </div>
        </form>
        </div>
    </body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    public  void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }
}

FindUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");

//        获取id
        String id = req.getParameter("id");
//        调用service查询
        UserService userService=new UserServiceImpl();
        User user=userService.findUserById(id);

//        将user存入request
            req.setAttribute("user",user);
            req.getRequestDispatcher("/update.jsp").forward(req,resp);

    }
}

UpdateUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
//        获取map
        Map<String, String[]> parameterMap = req.getParameterMap();
//        封装对象
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
//        调用service保存
        UserService userService=new UserServiceImpl();
        userService.updateUser(user);

//        转跳到userListServlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }
}

8 删除选中功能

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail3" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail4" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach var="user"  varStatus="s" items="${users}">
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
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                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }



}

DelSelectedServlet

package cn.gtt.web.servlet;

import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/delSelectedServlet")
public class DelSelectedServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取所有的id
        String[] uids = req.getParameterValues("uid");
//        调用service删除
        UserService userService=new UserServiceImpl();
        userService.delSelecteUser(uids);
        resp.sendRedirect(req.getContextPath()+"/userListServlet");

    }
}

9 分页

  1. 减轻服务器内存的开销
  2. 提升用户体验

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>


  <div >${user.name},欢迎您</div>
  <div align="center">
    <a
            href="${pageContext.request.contextPath}/findUserByPageServlet" target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
    </a>
  </div>






</body>
</html>

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;" >
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail3" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail4" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach items="${pb.list}" var="user"  varStatus="s" >
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <c:if test="${pb.currentPage==1}">
                    <li class="disabled">
                </c:if>

                <c:if test="${pb.currentPage!=1}">
                    <li >
                </c:if>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5" target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>


                <c:forEach begin="1" end="${pb.totalPage}" var="i">

                    <c:if test="${pb.currentPage==i}">
                        <li class="active">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>

                    <c:if test="${pb.currentPage!=i}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>
                </c:forEach>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5" target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共${pb.totalCount}条记录,共${pb.totalPage}页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     */
    int findTotalCount();

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @return
     */
    List<User> findByPage(int start,int rows);

}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     */
    @Override
    public int findTotalCount() {
        String sql="select count(*) from user";
        return jdbcTemplate.queryForObject(sql,Integer.class);
    }

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @return
     */
    @Override
    public List<User> findByPage(int start, int rows) {
        String sql="select * from user limit ?,?";

        return jdbcTemplate.query(sql,new BeanPropertyRowMapper<User>(User.class),start,rows);
    }


}

UserService

package cn.gtt.service;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

    /**
     * 分页查询
     */
    Page<User> findUserByPage(String currentPage, String rows);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }

    /**
     * 分页查询
     * @return
     */
    @Override
    public Page<User> findUserByPage(String _currentPage, String _rows) {

        int currentPage=Integer.parseInt(_currentPage);
        int rows=Integer.parseInt(_rows);

        if (currentPage<=0){
            currentPage=1;
        }

//        创建空的page对象
        Page<User> pb = new Page<User>();
//        设置参数
        pb.setCurrentPage(currentPage);
        pb.setRows(rows);
//        调用dao查询总记录数
        int totalCount=userDao.findTotalCount();
        pb.setTotalCount(totalCount);
//        调用dao查询list集合
//        计算开始的记录
        int start=(currentPage-1)*rows;
        List<User> list=userDao.findByPage(start,rows);
        pb.setList(list);
//        计算总页码
        int totalPage=totalCount%rows==0?totalCount/rows:(totalCount/rows+1);
        pb.setTotalPage(totalPage);
//        http://localhost:8080/findUserByPageServlet?currentPage=1&rows=5
        System.out.println(pb);
        return pb;
    }


}

FindUserByPageServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取参数
//        当前页码
        String currentPage = req.getParameter("currentPage");
//        每页显示的记录数
        String rows = req.getParameter("rows");

        if(currentPage==null||"".equals(currentPage)){
            currentPage="1";
        }
        if(rows==null||"".equals(rows)){
            rows="5";
        }

        

//        调用service查询
        UserService userService=new UserServiceImpl();
        Page<User> pb=userService.findUserByPage(currentPage,rows);

//        将Page存入request
        req.setAttribute("pb",pb);

//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);



    }
}

10 复杂查询

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;" >
        <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2" name="name" value="${condition.name[0]}">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="text" class="form-control" id="exampleInputEmail3" name="address"  value="${condition.address[0]}">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="text" class="form-control" id="exampleInputEmail4" name="email" value="${condition.email[0]}">
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach items="${pb.list}" var="user"  varStatus="s" >
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <c:if test="${pb.currentPage==1}">
                    <li class="disabled">
                </c:if>

                <c:if test="${pb.currentPage!=1}">
                    <li >
                </c:if>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>


                <c:forEach begin="1" end="${pb.totalPage}" var="i">

                    <c:if test="${pb.currentPage==i}">
                        <li class="active">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>

                    <c:if test="${pb.currentPage!=i}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>
                </c:forEach>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共${pb.totalCount}条记录,共${pb.totalPage}页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;
import java.util.Map;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     * @param condition
     */
    int findTotalCount(Map<String, String[]> condition);

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @param condition
     * @return
     */
    List<User> findByPage(int start, int rows, Map<String, String[]> condition);

}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     * @param condition
     */
    @Override
    public int findTotalCount(Map<String, String[]> condition) {
//        查询总记录数
//        String sql="select count(*) from user";
//        return jdbcTemplate.queryForObject(sql,Integer.class);

//        定义模板初始化sql
        String sql="select count(*) from user where  1=1";
        StringBuffer sb=new StringBuffer(sql);
//        遍历map
        Set<String> keySet = condition.keySet();
//        定义一个参数的集合
        List<Object> params = new ArrayList<>();
        for(String key:keySet){
//            排除分页条件
            if("currentPage".equals(key)||"rows".equals(key)){
                continue;
            }
//            根据键获取value
            String value = condition.get(key)[0];
//            判断value是否有值
            if(value!=null&&!"".equals(value)){
//                有值
                sb.append("   and "+key+" like ?");
//                ?条件的值
                params.add("%"+value+"%");
            }
        }
        System.out.println(sb.toString());
        System.out.println(params);
        return jdbcTemplate.queryForObject(sb.toString(),Integer.class,params.toArray());

    }

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @param condition
     * @return
     */
    @Override
    public List<User> findByPage(int start, int rows, Map<String, String[]> condition) {
        String sql="select * from user where 1=1  ";
        StringBuffer sb=new StringBuffer(sql);
//        遍历map
        Set<String> keySet = condition.keySet();
//        定义一个参数的集合
        List<Object> params = new ArrayList<>();
        for(String key:keySet){
//            排除分页条件
            if("currentPage".equals(key)||"rows".equals(key)){
                continue;
            }
//            根据键获取value
            String value = condition.get(key)[0];
//            判断value是否有值
            if(value!=null&&!"".equals(value)){
//                有值
                sb.append("   and "+key+" like ?");
//                ?条件的值
                params.add("%"+value+"%");
            }
        }

//        添加分页查询
        sb.append("limit ?,?");
        params.add(start);
        params.add(rows);

        return jdbcTemplate.query(sb.toString(),new BeanPropertyRowMapper<User>(User.class),params.toArray());
    }


}


package cn.gtt.service;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;

import java.util.List;
import java.util.Map;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

    /**
     * 分页条件查询
     *
     * 条件condition
     */
    Page<User> findUserByPage(String currentPage, String rows, Map<String, String[]> condition);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;
import java.util.Map;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }

    /**
     * 分页条件查询
     *
     * 条件condition
     */
    @Override
    public Page<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {

        int currentPage=Integer.parseInt(_currentPage);
        int rows=Integer.parseInt(_rows);

        if (currentPage<=0){
            currentPage=1;
        }

//        创建空的page对象
        Page<User> pb = new Page<User>();
//        设置参数
        pb.setCurrentPage(currentPage);
        pb.setRows(rows);
//        调用dao查询总记录数
        int totalCount=userDao.findTotalCount(condition);
        pb.setTotalCount(totalCount);
//        调用dao查询list集合
//        计算开始的记录
        int start=(currentPage-1)*rows;
        List<User> list=userDao.findByPage(start,rows,condition);
        pb.setList(list);
//        计算总页码
        int totalPage=totalCount%rows==0?totalCount/rows:(totalCount/rows+1);
        pb.setTotalPage(totalPage);
//        http://localhost:8080/findUserByPageServlet?currentPage=1&rows=5
        System.out.println(pb);
        return pb;
    }


}

FindUserByPageServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Map;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");

        //        获取参数
//        当前页码
        String currentPage = req.getParameter("currentPage");
//        每页显示的记录数
        String rows = req.getParameter("rows");

        if(currentPage==null||"".equals(currentPage)){
            currentPage="1";
        }
        if(rows==null||"".equals(rows)){
            rows="5";
        }

//        获取条件查询参数
        Map<String, String[]> condition = req.getParameterMap();

//        调用service查询
        UserService userService=new UserServiceImpl();
        Page<User> pb=userService.findUserByPage(currentPage,rows,condition);

//        将Page存入request
        req.setAttribute("pb",pb);
//        将查询条件存起来
        req.setAttribute("condition",condition);
//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);



    }
}