spring @condition 注解

spring @condition注解是用来在不同条件下注入不同实现的

demo如下:

package com.foreveross.service.weixin.test.condition;

import org.springframework.context.annotation.Condition;

import org.springframework.context.annotation.ConditionContext;

import org.springframework.core.type.AnnotatedTypeMetadata;

/**

 *

 * windows下的环境

 *

 */

public class WindowsCondition implements Condition{

    @Override

    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

        return context.getEnvironment().getProperty("os.name").contains("Windows");

    }

}

package com.foreveross.service.weixin.test.condition;

import org.springframework.context.annotation.Condition;

import org.springframework.context.annotation.ConditionContext;

import org.springframework.core.type.AnnotatedTypeMetadata;

public class LinuxCondition implements Condition{

    @Override

    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {

        return context.getEnvironment().getProperty("os.name").contains("Linux");

    }

}

package com.foreveross.service.weixin.test.condition;

public interface ListService {

    String showListCmd();

}

package com.foreveross.service.weixin.test.condition;

import org.springframework.stereotype.Service;

@Service

public class LinuxService implements ListService {

    public String showListCmd(){

        return "ls";

    }

}

package com.foreveross.service.weixin.test.condition;

import org.springframework.stereotype.Service;

@Service

public class WindowsService implements ListService{

    public String showListCmd(){

        return "dir";

    }

}

package com.foreveross.service.weixin.test.condition;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Conditional;

import org.springframework.context.annotation.Configuration;

@Configuration

public class MyConfiguration {

    @Bean(name = "service")

    @Conditional(WindowsCondition.class)

    public ListService windowsService() {

        return new WindowsService();

    }

    @Bean(name = "service")

    @Conditional(LinuxCondition.class)

    public ListService linuxEmailerService() {

        return new LinuxService();

    }

}

package com.foreveross.service.weixin.test.condition;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Test {

    public static void main(String[] args) {

        AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(MyConfiguration.class);

        ListService service= context.getBean(ListService.class);

        System.out.println("操作符为:"+service.showListCmd()+",系统为:"+context.getEnvironment().getProperty("os.name"));

        context.close();

    }

}