Spring Event观察者模式事件监听详解

@Data
public class OrderProductEvent extends ApplicationEvent {
  /** 该类型事件携带的信息 */
  private String orderId;
  public OrderProductEvent(Object source, String orderId) {
    super(source);
    this.orderId = orderId;
  }
}

/**
 * 实现 ApplicationListener 接口，并指定监听的事件类型
 */
@Slf4j
@Component
public class OrderProductListener implements ApplicationListener<OrderProductEvent> {
  /**
   *  使用 onApplicationEvent 方法对消息进行接收处理
   *  
   * */
  @SneakyThrows
  @Override
  public void onApplicationEvent(OrderProductEvent event) {
    String orderId = event.getOrderId();
    long start = System.currentTimeMillis();
    Thread.sleep(2000);
    long end = System.currentTimeMillis();
    log.info("{}：校验订单商品价格耗时：({})毫秒", orderId, (end - start));
  }
}

@Slf4j
@Service
@RequiredArgsConstructor
public class OrderService {
  /** 注入ApplicationContext用来发布事件 */
  private final ApplicationContext applicationContext;
  /**
   * 下单
   *
   * @param orderId 订单ID
   */
  public String buyOrder(String orderId) {
    long start = System.currentTimeMillis();
    // 1.查询订单详情
    // 2.检验订单价格 （同步处理）
    applicationContext.publishEvent(new OrderProductEvent(this, orderId));
    long end = System.currentTimeMillis();
    log.info("任务全部完成，总耗时：({})毫秒", end - start);
    return "购买成功";
  }
}

@SpringBootTest
public class OrderServiceTest {
  @Autowired
  private OrderService orderService;
  @Test
  public void buyOrderTest() {
    orderService.buyOrder("732171109");
  }
}

import lombok.AllArgsConstructor;
import lombok.Data;
@Data
@AllArgsConstructor
public class MsgEvent {
  /** 该类型事件携带的信息 */
  public String orderId;
}

@Slf4j
@Component
public class MsgListener {
  @Async
  @SneakyThrows
  @EventListener(MsgEvent.class)
  public void sendMsg(MsgEvent event) {
    String orderId = event.getOrderId();
    long start = System.currentTimeMillis();
    log.info("开发发送短信");
    log.info("开发发送邮件");
    Thread.sleep(4000);
    long end = System.currentTimeMillis();
    log.info("{}：发送短信、邮件耗时：({})毫秒", orderId, (end - start));
  }
}

@Slf4j
@Service
@RequiredArgsConstructor
public class OrderService {
  /** 注入ApplicationContext用来发布事件 */
  private final ApplicationContext applicationContext;
  /**
   * 下单
   *
   * @param orderId 订单ID
   */
  public String buyOrder(String orderId) {
    long start = System.currentTimeMillis();
    // 1.查询订单详情
    // 2.检验订单价格 （同步处理）
//    applicationContext.publishEvent(new OrderProductEvent(this, orderId));
    // 3.短信通知（异步处理） 新开线程执行监听得业务
    applicationContext.publishEvent(new MsgEvent(orderId));
    long end = System.currentTimeMillis();
    log.info("任务全部完成，总耗时：({})毫秒", end - start);
    return "购买成功";
  }
}

@EnableAsync
@EnableRetry
@SpringBootApplication
public class LlpSpringRetryApplication {
    public static void main(String[] args) {
        SpringApplication.run(LlpSpringRetryApplication.class, args);
    }
}