一、介绍

监听器的简化写法

二、原理

三、使用

@Slf4j
@Component
public class MyTask {
    @EventListener
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ContextRefreshedEvent) {
            log.info("监听到 ContextRefreshedEvent...");
        }
        if (event instanceof MyEvent) {
            log.info("监听到 MyEvent...");
            MyEvent myEvent = (MyEvent) event;
            System.out.println("时间：" + myEvent.getTime() + " 信息：" + myEvent.getMsg());
        }
    }
}

@Slf4j
@Component
public class MyTask {
    @EventListener
    public void MyEventListener(MyEvent event) {
        log.info("监听到 MyEvent...");
        MyEvent myEvent = (MyEvent) event;
        System.out.println("时间：" + myEvent.getTime() + " 信息：" + myEvent.getMsg());
    }

    @EventListener
    public void ContextRefreshedEventListener(MyEvent event) {
        log.info("监听到 ContextRefreshedEvent...");
    }
}

 还可以指定监听事件的类型：

@EventListener(MyEvent.class)

@EventListener({MyEvent.class, ContextRefreshedEvent.class})

四、demo

在前面的基础上，改造listener的写法：

package com.listener.demo.listener;

import com.listener.demo.dto.UserLogDTO;
import com.listener.demo.event.MyLogEvent;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Slf4j
@Component
public class MyListener {

    @EventListener
    public void onApplicationEvent(MyLogEvent event) {
        UserLogDTO source = event.getSource();
        log.info("监听到:url={},detail={}",source.getUrl(),source.getDetail());
        //其他处理，比如存储日志
    }
}

访问localhost:4444/listenerDemo/user/add?userName=zhangsan&userAccount=zs，控制台也同样打印