Spring事件（Application Event）

Spring的事件（Application Event）为Bean与Bean之间的通信提供了支持。当一个Bean处理完一个任务时，希望另一个Bean知道并能做相应的处理，这时我们就需要让另外一个Bean监听当前所发送的事件。

Demo:

自定义事件DemoEvent.java 继承ApplicationEvent

package com.example.mavenspringmvc.event;
import org.springframework.context.ApplicationEvent;

/**
* 定义一个事件，继承ApplicationEvent
*/
public class DemoEvent extends ApplicationEvent{

private String eventMsg;

public DemoEvent(Object source, String eventMsg) {
super(source);
this.eventMsg = eventMsg;
}

public String getEventMsg() {
return eventMsg;
}

public void setEventMsg(String eventMsg) {
this.eventMsg = eventMsg;
}
}

自定义事件监听器DemoEventListener.java 实现ApplicationListener接口，并指定监听的事件类型，使用onApplicationEvent方法对消息进行接受处理

package com.example.mavenspringmvc.event;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

@Component
public class DemoEventListener implements ApplicationListener<DemoEvent>{

@Override
public void onApplicationEvent(DemoEvent demoEvent) {
String msg = demoEvent.getEventMsg();
System.out.println("我收到了消息：" + msg);
}
}

事件发布类DemoEventPublisher.java

package com.example.mavenspringmvc.event;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

/**
* 事件发布类，需使用spring容器来发布事件，即ApplicationContext来发布
*/
@Component
public class DemoEventPublisher {

@Autowired
private ApplicationContext applicationContext;

public void publishDemoEvent(String eventMsg){
applicationContext.publishEvent(new DemoEvent(this,eventMsg));
}
}

测试类TestEventService.java

package com.example.mavenspringmvc.event;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class TestEventService {

@Autowired
private DemoEventPublisher demoEventPublisher;

public void publishEvent(){
demoEventPublisher.publishDemoEvent("hello application event");
}
}

运行结果：