java - @TransactionalEventListener 在@EventListener 像相同上下文的魅力一样工作的地方不起作用

Question

我正在从事 spring boot 应用程序的事件驱动设计。

代码由以下文件组成:

1. Spring boot:ApplicationEvent 文件，即 MyBusinessEvent.{java

   @Data
   @AllArgsConstructor
   public class MyBusinessEvent {
   
      private String data;
   
   }
   

2. 事件发布者文件:MyBusinessService.java

   @Slf4j
   @Service
   public class MyBusinessService {
   
       private final ApplicationEventPublisher applicationEventPublisher;
   
       @Autowired
       public MyBusinessService(
               ApplicationEventPublisher applicationEventPublisher) {
   
           this.applicationEventPublisher = applicationEventPublisher;
       }
   
       @Override
       public void save() {
           String data = "Testing event data";
           MyBusinessEvent event = new MyBusinessEvent(data);
           applicationEventPublisher.publishEvent(event);
       }
   }
   

3. 事件监听器:MyBusinessEventListener.java

   @Slf4j
   @Component
   public class MyBusinessEventListener {
   
       @EventListener
       public void handleEvent(MyBusinessEvent myBusinessEvent) {
           log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
       }
   }
   

重点是当监听器文件包含 @EventListener 时，应用程序会按预期工作，但当我执行 @TransactionEventListener 时。例如:

1. 事务事件监听器:MyBusinessEventListener.java

   @Slf4j
   @Component
   public class MyBusinessEventListener {
   
       @TransactionalEventListener
       public void handleEvent(MyBusinessEvent myBusinessEvent) {
           log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
       }
   }
   

使用@TransactionalEventListener，它根本不起作用。

应用程序没有遇到任何异常(甚至在运行时也没有)，但没有按预期进行日志记录。

是否缺少任何配置？

Answer 1

将 @Transactional 注释添加到 MyBusinessService.save 应该可以解决这个问题。

根据 java 文档，@TransactionalEventListener 在 @Transactional 边界内工作。

这是文档所说的，

If the event is not published within the boundaries of a managed transaction, the
 * event is discarded unless the {@link #fallbackExecution} flag is explicitly set.

如果您不想在事务边界中使用您的服务方法，请使用 @TransactionalEventListener(fallbackExecution = true)

编辑:对于上述问题，存在三种可能的解决方案。

我。将 class 标记为 @Transactional 以被视为事务性

@Transactional
@Service
public class MyBusinessService {

    private final ApplicationEventPublisher applicationEventPublisher;

    @Autowired
    public MyBusinessService(
            ApplicationEventPublisher applicationEventPublisher) {

        this.applicationEventPublisher = applicationEventPublisher;
    }

    @Override
    public void save() {
        String data = "Testing event data";
        MyBusinessEvent event = new MyBusinessEvent(data);
        applicationEventPublisher.publishEvent(event);
    }
 }

二。将service的具体方法做成@Transactional

@Override
@Transactional
public void save() {
    String data = "Testing event data";
    MyBusinessEvent event = new MyBusinessEvent(data);
    applicationEventPublisher.publishEvent(event);
}

三。如果您不想在事务边界中使用您的服务方法，请使用

@Slf4j
@Component
public class MyBusinessEventListener {

    @TransactionalEventListener(fallbackExecution = true)
    public void handleEvent(MyBusinessEvent myBusinessEvent) {
        log.info("[MyBusinessEventListener] New event received with following data: {}", myBusinessEvent);
    }
}