spring @condition 注解

spring @condition注解是用來在不同條件下注入不同實現的

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下的環境
 *
 */
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("操作符為:"+service.showListCmd()+",系統為:"+context.getEnvironment().getProperty("os.name"));
        
        context.close();
    }
}