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Spring源码分析(五)-注解@Conditional条件注册bean

Conditional条件注册bean

假设有这么一个场景，需要根据操作系统加载不同的实例

将IOC容器注册bean时, 当操作系统为WINDOWS时,注册caojiulu实例; 当操作系统为LINUX时, 注册hujinxiao实例,此时要用得@Conditional注解进行定制化条件选择注册bean

新建Cap5MainConfig.java

package com.caojiulu.cap5.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

import com.caojiulu.cap1.bean.Person;
import com.caojiulu.cap5.condition.LinuxCondition;
import com.caojiulu.cap5.condition.WinConditin;

@Configuration
public class Cap5MainConfig {

	@Conditional({WinConditin.class})
	@Bean
	public Person caojiulu(){
		return new Person("caojiulu",20);
	}
	@Conditional({LinuxCondition.class})
	@Bean
	public Person huinxiao(){
		return new Person("huinxiao",28);
	}
}

新建WinConditin.java

package com.caojiulu.cap5.condition;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.env.Environment;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.type.AnnotatedTypeMetadata;

public class WinConditin implements Condition{

	/**
	 * ConditionContext :上下文环境
	 * AnnotatedTypeMetadata ： 注释信息
	 */
	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
		//是否window系统
		
		//获取beanFactory
		ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
		//获取类加载器
		ResourceLoader resourceLoader = context.getResourceLoader();
		//获取环境信息
		Environment environment = context.getEnvironment();
		//获取bean定义的注册类
		BeanDefinitionRegistry registry = context.getRegistry();
		String property = environment.getProperty("os.name");
		if(property.contains("Windows")){
			return true;
		}
		return false;
	}

	
}

新建LinuxCondition.java

package com.caojiulu.cap5.condition;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.env.Environment;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.type.AnnotatedTypeMetadata;

public class LinuxCondition implements Condition{

	/**
	 * ConditionContext :上下文环境
	 * AnnotatedTypeMetadata ： 注释信息
	 */
	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
		//是否window系统
		
		//获取beanFactory
		ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
		//获取类加载器
		ResourceLoader resourceLoader = context.getResourceLoader();
		//获取环境信息
		Environment environment = context.getEnvironment();
		//获取bean定义的注册类
		BeanDefinitionRegistry registry = context.getRegistry();
		String property = environment.getProperty("os.name");
		if(property.contains("linux")){
			return true;
		}
		return false;
	}

	
}

测试类：

模拟linux环境：