Spring Event Handling for prototype components

问题

Let say I have two components X and Y, where X is singleton and Y is not.

when I publish XUpdateEvent, there is no problem, I can catch the event. However, for YUpdateEvent's I cannot catch events. Spring creates new instances for each fired event, not using the already created ones.

So, Should I need to write a custom scope? or EventListener has settings?

To illustrate:

@Component
public class X{
 @EventListener
 public void onUpdate(XUpdateEvent event){
 // fine.
 }
}

@Component
@Scope("prototype")
public class Y{
 @EventListener
 public void onUpdate(YUpdateEvent event){
 // calls new instance of Y for each event.
 // Event should be fired for created instances.
 }
}

回答1:

Spring creates new instances for each fired event, not using the already created ones

This is what prototype scope means. Have a look at the docs.

The non-singleton, prototype scope of bean deployment results in the creation of a new bean instance every time a request for that specific bean is made.

If you want that Spring reuses your Y instance, declare it as singleton (i.e. define no @Scope at all)

来源：https://stackoverflow.com/questions/33368341/spring-event-handling-for-prototype-components