Spring Event事件发布&消费Demo

demo基于springboot maven项目

spring event默认是同步执行的，因此后面示范了如何异步执行事件的监听函数，以及配置自己的异步线程池

pom.xml

		<!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--spring web-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- springboot devtools-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <!-- spring configuration processor-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

实现自己的事件

package com.example.demo.event;

import lombok.Getter;
import lombok.ToString;
import org.springframework.context.ApplicationEvent;

/**
 * @Author humorchen
 * @Date 2021/10/25
 */
@Getter
@ToString
public class NoticeEvent extends ApplicationEvent {
    /**
     * 标题
     */
    private String title;
    /**
     * 内容
     */
    private String content;



    public NoticeEvent(String title,String content) {
        super(title);
        this.title = title;
        this.content = content;
    }


}

定义事件监听器

package com.example.demo.listener;

import com.example.demo.event.NoticeEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Component;

/**
 * @Author humorchen
 * @Date 2021/10/25
 */
@Component
public class NoticeEventListener implements ApplicationListener<NoticeEvent> {

    @Async
    @Override
    public void onApplicationEvent(NoticeEvent noticeEvent) {
        System.out.println(Thread.currentThread().getName() + "线程处理事件");
        System.out.println(noticeEvent);
    }
}

定义事件发布接口

package com.example.demo.controller;

import com.example.demo.event.NoticeEvent;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Author humorchen
 * @Date 2021/10/25
 */
@RestController
public class EventPublisherController {

    /**
     * 注入spring 事件发布器
     */
    @Autowired
    private ApplicationEventPublisher eventPublisher;


    @RequestMapping("/publish")
    public String publish(String title,String content){
        NoticeEvent event = new NoticeEvent(title,content);
        System.out.println("接口收到请求，内容如下：");
        System.out.println(event);
        eventPublisher.publishEvent(event);
        String ret = "事件发布成功";
        System.out.println(ret);
        return ret;
    }
}

走异步线程池执行监听函数

• 给启动类加@EnableAsync注解
• 给消费函数加@Async注解

定义自己的spring异步线程池

package com.example.demo.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;

/**
 * @Author humorchen
 * @Date 2021/10/25
 */
@Configuration
public class AsyncConfig implements AsyncConfigurer {

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(4);
        executor.setMaxPoolSize(16);
        executor.setQueueCapacity(Integer.MAX_VALUE);
        executor.setThreadNamePrefix("async-thread-");
        executor.initialize();
        return executor;
    }
}

发送请求

http://localhost/publish?title=放假&content=明天放假

执行结果

接口收到请求，内容如下：
NoticeEvent(title=放假, content=明天放假)
2021-10-25 15:30:04.414  INFO 10088 --- [p-nio-80-exec-1] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService
事件发布成功
async-thread-1线程处理事件
NoticeEvent(title=放假, content=明天放假)