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一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一
追加文件内容
 import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;

public class AppendToFile {
   
    public static void appendMethodA(String fileName, String content) {
        try {
            // 打开一个随机访问文件流，按读写方式
            RandomAccessFile randomFile = new RandomAccessFile(fileName, "rw");
            // 文件长度，字节数
            long fileLength = randomFile.length();
            //将写文件指针移到文件尾。
            randomFile.seek(fileLength);
            randomFile.writeBytes(content);
            randomFile.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

   
    public static void appendMethodB(String fileName, String content) {
        try {
            //打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件
            FileWriter writer = new FileWriter(fileName, true);
            writer.write(content);
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        String fileName = "E:/newTemp.dat";
        String content = "new append!";
        //按方法A追加文件
        AppendToFile.appendMethodA(fileName, content);
        AppendToFile.appendMethodA(fileName, "append end.");
        //显示文件内容
        ReadFromFile.readFileByBytes(fileName);//.readFileByLines(fileName);
      
       // ReadFromFile.readFileByLines(fileName);
    }
}


      public void putRun(String s ) {
          String runPath = "mnt/sdcard/wlk/log/log.txt" ;
           try {
              FileWriter fw = null ;
          // true为在文本末尾追加
               fw = new FileWriter( runPath , true );
               fw .write( s );
               fw .flush();
               fw .close();
          } catch (Exception e ) {           
          }
     }

一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一
向文件中添加内容
String str=“SB”;

FileWriter fw=new FileWriter("D:\\log.txt");
fw.write(str);
fw.flush();
fw.close();

一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一

创建文件
File file = new File(Environment.getExternalStorageDirectory() + File.separator + "");
(SD卡目录，文件分割符，文件名) 声明一个文件
if(file.exists){//判断文件是否存在
file.delete;//存在就删除
file.createNewFile//创建文件
}

ouyputStream ot = new FileOutputStream(file,true)//文件输出流
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"><uses-permission>


break  跳出一层循环
加注释跳出注释那层
in:
for (){
for(){
 break in;
  }
}
一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一
刷新媒体库
  //filename是我们的文件全名，包括后缀
         private void updateGallery(String filename ){
              MediaScannerConnection.scanFile( this ,
               new String[] { filename }, null ,
               new MediaScannerConnection.OnScanCompletedListener() {
               public void onScanCompleted(String path , Uri uri ) {
               Log.i( "ExternalStorage" , "Scanned " + path + ":" );
               Log.i( "ExternalStorage" , "-> uri=" + uri );
               }
               });
          }


      //filename是我们的文件全名，包括后缀哦（在广播中使用）
    private void updateGallery(String filename ){
     
          MediaScannerConnection.scanFile( c .getApplicationContext(),
           new String[] { filename }, null ,
           new MediaScannerConnection.OnScanCompletedListener() {
           public void onScanCompleted(String path , Uri uri ) {
           }
           });
     }



一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一

创建删除写入文件权限   
     <!--往sdcard中写入数据的权限 -->
     < uses-permission android:name = "android.permission.WRITE_EXTERNAL_STORAGE" />
     <!--在sdcard中创建/删除文件的权限 -->
     < uses-permission android:name = "android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

一一一一一一一一一一一一一一一一   一一一一   我是一条你看不见的分割线一一一一一一一一一一一一一一一一一一一一一一一一一

读取文件信息并一行一行的显示
File file=new File("/mnt/sdcard/aa.txt");
  FileReader fr=new FileReader(file);
  BufferedReader br=new BufferedReader(fr);
  String temp=null;
  String s="";
  while((temp=br.readLine())!=null){
   s+=temp+"\n";
  }
  String [] ss=s.split("\n");
  for (int i = 0; i < ss.length; i++) {
   System.out.println(ss[i]);
  }




一一一一一一一一一一一一一一一一我是一条分割线一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一



      public StringFileOut(String path ) throws IOException {
          String content = "" ; // 文件内容字符串
           // 打开文件
          File file = new File( path );
           // 如果path是传递过来的参数，可以做一个非目录的判断
           if ( file .isDirectory()) {
          } else {
              BufferedReader in = new BufferedReader( new InputStreamReader( new FileInputStream( file ), "UTF-8" ));
               if ( in != null ) {
                   String line ;
                    // 分行读取
                    while (( line = in .readLine()) != null ) {
                         content += line ;

                    // coordinate = line .split( "\\," );   分行读取到逗号后的数据
                   }
                    in .close();
              }
          }
           return content ;

     }

一一一一一一一一一一一一一一一一我是一条你看不见的分割线一一一一一一一一一一一一一一一一一一

      public String FileOut(String path , String jsonContent ) throws IOException {
          String content = "" ; // 文件内容字符串
           // 打开文件
          File file = new File( path );
           // 如果path是传递过来的参数，可以做一个非目录的判断
           if ( file .isDirectory()) {
          } else {
              BufferedReader in = new BufferedReader( new InputStreamReader( new FileInputStream( file ), "UTF-8" ));
               if ( in != null ) {
                   String line ;
                    // 分行读取
                    while (( line = in .readLine()) != null ) {
                         content += line ;
                   }
                    in .close();
              }
          }
           return content ;

     }

一一一一一一一一一一一一一一一一我是一条你看不见的分割线一一一一一一一一一一一一一一一一一一

刷新媒体库
      // filename是我们的文件全名，包括后缀哦
      private void updateGallery(String filename ) {

          MediaScannerConnection.scanFile( c , new String[] { filename }, null ,
                    new MediaScannerConnection.OnScanCompletedListener() {
                         public void onScanCompleted(String path , Uri uri ) {
                        }
                   });
     }