spring学习--7 event

过程：定义一个event和一个listener，再在event publisher class中通过ApplicationEvent.publishEvent(java.lang.Object event)方法发布事件。

1、Event

package com.event;

import org.springframework.context.ApplicationEvent;

public class DemoEvent extends ApplicationEvent {
    private static final long serialVersionUID = 1L;

    private String msg;

    public DemoEvent(Object source, String msg) {
        // ApplicationEvent is contract, so must pick up another constructor(the one of EventObject) to initialize instance.
        super(source);
        this.msg = msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public String getMsg() {
        return msg;
    }
}

2、Listener

package com.event;

import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

// This annotation must exist, otherwise container can instantiate the bean to listen message
@Component
public class DemoListener implements ApplicationListener<DemoEvent>{
    @Override
    public void onApplicationEvent(DemoEvent event) {
        String msg = event.getMsg();
        System.out.println("I'm a application event listener, I've received a message from event publisher: " + msg);
    }
}

3、Event Publisher(ie source)

package com.event;

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

@Component
public class DemoPublisher {
    @Autowired
    ApplicationContext applicationContext;

    public void publish(String msg) {
        applicationContext.publishEvent(new DemoEvent(this, msg));
    }
}

4、Configutaion

package com.event;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan("com.event")
public class EventConfig {  

}

5、Test

package com.event;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Bootrap {
    public static void main(String[] args) {
        AnnotationConfigApplicationContext context =
                new AnnotationConfigApplicationContext(EventConfig.class);

        DemoPublisher publisher  = context.getBean(DemoPublisher.class);
        publisher.publish("Hello, application event listener.");

        context.close();
    }
}