春天的事件监听器被调用了两次 [英] Event Listeners in spring is called twice
问题描述
我是Spring事件侦听器的问题，在我的Web应用程序中，我们将不胜感激.
I am an issue with Spring Event Listeners In my Web app, Any immediate help will be appreciated.
事件侦听器被注册并调用两次(如果我具有循环依赖性).
我有服务类，该类在其他方法上具有@transaction注释
I have service class, this has @transaction annotation on another methods
@Service(PBSTaskService.BEAN_NAME)
public class PBSTaskServiceImpl extends StandardServiceImpl<ITask> implements PBSTaskService,ApplicationListener<SurveyDefinitionPublishedEvent>
{
@Autowired
private AutoSelectTaskSliceRouteSyncService autoSelectTaskSliceRouteSyncService; // CYCLIC Dependency
@Override
public void onApplicationEvent(SurveyDefinitionPublishedEvent event)
{
System.out.println("PBSTSImpl"); // THIS IS CALLED TWICE
}
... Other method with @Transaction Annotation
}
@Service(AutoSelectTaskSliceRouteSyncService.BEAN_NAME)
public class AutoSelectTaskSliceRouteSyncServiceImpl implements AutoSelectTaskSliceRouteSyncService
{
@Autowired private PBSTaskService pbsTaskService; // CYCLIC dependency
}
现在，如果我从头等舱中删除AutoSelectTaskSliceRouteSyncSyncService依赖项，则一次调用OnApplicationEvent，否则调用两次.
Now If I remove AutoSelectTaskSliceRouteSyncService dependency from First Class, OnApplicationEvent is called once, else twice.
我调试了一下，发现 SimpleApplicationEventMulticaster.getApplicationListeners(myEvent):有两个代理对象，一个用Cglib包装，另一个用默认对象包装.但是只有在具有循环依赖性的情况下才有两个.如果我删除循环依赖项，则它只有一个代理对象，而CGLIB增强了该代理对象. 我的Tx批注: 我曾尝试使用proxy-target-class ="true或false"，但没有运气.
I debugged and found out that SimpleApplicationEventMulticaster.getApplicationListeners(myEvent) : Has two proxy object, one wrapped with Cglib and another default one. But it has two only in case if it has cyclic dependency. If I remove Cyclic dependency, it has only one proxy object and that one is enahnces by CGLIB. my Tx annotation : I had tried it with proxy-target-class="true or false" but no luck.
您可能想看看
推荐答案
ApplicationEvent侦听器在我们的Web应用程序的更多位置被两次调用.这是我们遇到的情况之一.
ApplicationEvent Listeners are called twice at many more places in our web app. This is one of scenarios that we caught up.
原因: 侦听器被注册两次.返回两个代理，它们包装在一个侦听器实例上.返回的代理是1.动态Jdk接口代理2.带有@transactions批注的Cglib代理.
Reason : Listeners are registered twice. Two proxy are returned wrapped over one instance of listeners. Proxy returned are 1. Dynamic Jdk Interface proxy 2. Cglib Proxy, when we have @transactions annotations.
要重新创建这三点，必须:
To recreate these three point are must:
- 您的侦听器必须实现ApplicationListener2.您的侦听器必须与另一个类3具有循环依赖关系.您的侦听器必须具有一个@Transaction注释的方法.
我创建了一个单独的项目，可以在其中使用spring和hibernate进行复制.如果2和3不能同时出现，那么我们是安全的.
I have created a separate project where I am able to reproduce it with spring and hibernate. If 2 and 3 are not present together, then we are safe.
解决方案 我尝试了很多关于spring和transaction配置的调整，但是没有运气.最后，在我的演示项目中，将事务处理代码移至另一个类，以便侦听器没有任何@transaction注释，然后它对我有用.
Solution I tried many tweaks with spring and transaction configuration but no luck. Then finally with my demo project when I moved the transaction code to another class, so that the listeners do not have any @transaction annotations then it worked for me.
这篇关于春天的事件监听器被调用了两次的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
