@Data
public class OrderEvent extends ApplicationEvent {  // 第一步 extends ApplicationEvent

   // 可添加多個(gè)字段
    public String message;

  	// 根據(jù)需要添加字段
    public OrderEvent(Object source, String message) {
        // 固定寫(xiě)法
        super(source);  
        this.message = message;
    }

}

@RestController
@RequestMapping("order")
public class OrderController {

    // 第一步
    @Autowired
    private ApplicationContext applicationContext;

    @GetMapping("/createOrder/{orderNo}")
    public String createOrder(@PathVariable String orderNo) {
      
      	// 第二步
        applicationContext.publishEvent(new OrderEvent(this, String.format("訂單創(chuàng)建成功，訂單號(hào)為：%s", orderNo)));
        return "訂單常見(jiàn)成功";
      
    }
}

@Component   // 第一步
public class GlobalListener {

    private static Logger logger = LoggerFactory.getLogger(GlobalListener.class);

    @EventListener(OrderEvent.class)  // 第二步
    public void createOrder(OrderEvent orderEvent) {
        logger.info("{} 監(jiān)聽(tīng)器接收到消息，訂單號(hào)為：{}", LocalDateTime.now(), orderEvent.getMessage());
    }
}

@Component		// 第一步
public class OrderListener implements ApplicationListener<OrderEvent> {		// 第一步 implements ApplicationListener<OrderEvent>

    private static Logger logger = LoggerFactory.getLogger(OrderListener.class);

  	// 第三步
    @Override
    public void onApplicationEvent(OrderEvent orderEvent) {
        logger.info("方式二： {} 監(jiān)聽(tīng)器接收到消息，訂單號(hào)為：{}", LocalDateTime.now(), orderEvent.getMessage());
    }
}

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.event.SmartApplicationListener;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;

@Component  // 第一步
public class SmartOrderListener implements SmartApplicationListener {

    private static Logger logger = LoggerFactory.getLogger(SmartOrderListener.class);

    /**
     * 該方法返回true&supportsSourceType同樣返回true時(shí)，才會(huì)調(diào)用該監(jiān)聽(tīng)內(nèi)的onApplicationEvent方法
     *
     * @param aClass 接收到的監(jiān)聽(tīng)事件類(lèi)型
     * @return
     */
    @Override
    public boolean supportsEventType(Class<? extends ApplicationEvent> aClass) {
        // 指定只有 OrderEvent 監(jiān)聽(tīng)類(lèi)型才會(huì)執(zhí)行下面邏輯
        return aClass == OrderEvent.class;
    }

    /**
     * 該方法返回true&supportsEventType同樣返回true時(shí)，才會(huì)調(diào)用該監(jiān)聽(tīng)內(nèi)的onApplicationEvent方法
     *
     * @param sourceType
     * @return
     */
    @Override
    public boolean supportsSourceType(Class<?> sourceType) {
        //只有在 OrderService 內(nèi)發(fā)布的 OrderEvent 事件時(shí)才會(huì)執(zhí)行下面邏輯，這里沒(méi)有，下面是案列
        // return aClass == OrderService.class;
        return SmartApplicationListener.super.supportsSourceType(sourceType);
    }

    /**
     * supportsEventType & supportsSourceType 兩個(gè)方法返回true時(shí)調(diào)用該方法執(zhí)行業(yè)務(wù)邏輯
     *
     * @param applicationEvent 具體監(jiān)聽(tīng)實(shí)例，這里是 OrderEvent
     */
    @Override
    public void onApplicationEvent(ApplicationEvent applicationEvent) {

        //轉(zhuǎn)換事件類(lèi)型
        OrderEvent orderEvent = (OrderEvent) applicationEvent;
        String message = orderEvent.getMessage();
        logger.info("方式三(有序)： {} 監(jiān)聽(tīng)器接收到消息，訂單號(hào)為：{}", LocalDateTime.now(), orderEvent.getMessage());
    }

    @Override
    public int getOrder() {
        return 0;
    }

}