Spring ApplicationEvent 事件处理--不用引入中间件

import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;
 
@Configuration
public class EventConfiguration {
 
    @Component
    public static class MyEvent extends ApplicationEvent {
        public MyEvent() {
            super("My Event Source");
        }
    }
 
    @Component
    public static class MyEventPublisher {
        private final ApplicationEventPublisher publisher;
 
        public MyEventPublisher(ApplicationEventPublisher publisher) {
            this.publisher = publisher;
        }
 
        public void publish() {
            publisher.publishEvent(new MyEvent());
        }
    }
 
    @Component
    public static class MyEventHandler implements ApplicationListener<MyEvent> {
        @Override
        public void onApplicationEvent(MyEvent event) {
            System.out.println("Event received: " + event.getSource());
        }
    }
 
    // 使用 @EventListener 注解的方式处理事件
    @Component
    public static class EventListenerHandler {
        @EventListener
        public void handleEvent(MyEvent event) {
            System.out.println("EventListener received: " + event.getSource());
        }
    }
}

这个代码示例展示了如何在Spring应用中定义和发布自定义事件，并使用ApplicationListener接口和@EventListener注解来处理这些事件。这是一个内置于Spring框架中的简单事件驱动机制，无需引入额外的中间件。