SpringBoot中使用监听器

1.定义一个事件

/*** 定义事件* @author hrui* @date 2024/7/25 12:46*/
public class CustomEvent extends ApplicationEvent {private String message;public CustomEvent(Object source, String message) {super(source);this.message = message;}public String getMessage() {return message;}
}

在监听器中可以通过 event.getSource();  来获取事件源

2.通过ApplicationEventPublisher 发布事件

@Service
public class EventPublisherService {@Autowiredprivate ApplicationEventPublisher applicationEventPublisher;public void publishEvent(String message) {CustomEvent event = new CustomEvent(this, message);applicationEventPublisher.publishEvent(event);}
}

3.通过监听器订阅事件

/*** 监听事件,订阅事件* @author hrui* @date 2024/7/25 12:49*/
@Component
public class CustomEventListener {@Async//@EventListener//@TransactionalEventListener 有事务的监听@EventListener(condition = "#event.message == 'hello'") //SPEL(Spring表达式)条件监听 对象也可以用== 判断//@EventListener(condition = "#event.message .equals('hello') ")//@EventListener(condition = "#event.message.endsWith("123") ") //很多方法可以选择public void handleCustomEvent(CustomEvent event) {System.out.println(Thread.currentThread().getName());System.out.println("Received event - " + event.getMessage());}
}

第三步简单实用了@EventListener注解  如果不用就需要这么做

去实现ApplicationListerner<处理的事件>  需不需要异步自己看着办

import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;@Component
public class CustomEventListener implements ApplicationListener<CustomEvent> {@Overridepublic void onApplicationEvent(CustomEvent event) {// 条件判断if ("hello".equals(event.getMessage())) {// 异步处理new Thread(() -> {System.out.println(Thread.currentThread().getName());System.out.println("Received event - " + event.getMessage());}).start();}}
}

/*** @author hrui* @date 2024/7/25 12:51*/
@RestController
public class ListenerController {@Autowiredprivate EventPublisherService eventPublisherService;@GetMapping("/listener")public String listener(String message){eventPublisherService.publishEvent(message);return "listener";}
}