Refresh data in stateless EJB

Is 开发者_StackOverflow社区there a function which is called every time an EJB is looked up? I need to refresh some data before any method is called.

Not sure I get exactly what you mean. First you probably need to distinguish between stateless and stateful EJBs.

• Stateless EJB are well, stateless, and should not contain data. The app. server can decide to destroy or reconstruct it anytime. You don't actually hold a reference to a particular instance which is created when it's looked up. The app. server maintain a pool of EJBs, and one of them is used per invocation.

• Stateful EJB can contain data. You hold a reference to one specific instance, which is created when the bean is looked up. Callback methods can be specified with @PostConstruct or @PreDestroy (These callbacks also exist for stateless EJBs but make less sense).

That said, if you need to perform something before a method is called, I suggest you use an interceptor (using @Interceptor, works for stateless and stateful EJBs). Just like with AOP, you get a chance to perform something before and after the bean method is actually executed, e.g refresh the cache.