Is it possible to inject EJB implementation and not its interface using CDI?

问题

My configuration is: Wildfly 8.2.0, Weld

Is it possible to inject in bean and not in its interface in CDI ?

@Stateless
class Bean implements IBean {
...
}    

interface IBean {
...
}

@SessionScoped
class Scoped {
   @Inject
   Bean bean; //Fail

   @Inject
   IBean iBean; //OK
}

EDIT:

More Info in my previous question: Stateless EJB implements interface injection failed

回答1:

Yes you can, but as EJB inject the business view the only business view you are exposing is the @Local view which is the default when you implement an interface (IBean in your case is a local business interface). So, if you want to inject the bean itself, you need to tell the container that you are using the no-interface view.

In your example, if you still want to implement your interface and inject Bean you should use the @LocalBean annotation which means that the bean exposes a no-interface view:

@Stateless
@LocalBean // <-- no-interface view
class Bean implements IBean {
...
}  

interface IBean {
....
}

@SessionScoped
class Scoped {
   @Inject
   Bean bean; //Should be OK
}

Or, If you don't want to implement any interface, then the bean defines by default a No-Interface view:

@Stateless
class Bean {
...
}  

@SessionScoped
class Scoped {
   @Inject
   Bean bean; //OK
}

See also:

• What is local/remote and no-interface view in EJB?
• Defining EJB 3.1 Views (Local, Remote, No-Interface)
• EJB 3.1 @LocalBean vs no annotation

回答2:

It looks like you got an unclear answer in your prior question, and really all this question is is a follow up to that one.

Generally speaking, CDI allows you to inject both interface and impl for CDI managed beans. This is not the case for EJBs. When an EJB implements an interface, that becomes its business interface. Only the methods declared there are valid. Effectively, your Bean class defines only how those methods work, and does not actually exist as a bean in your runtime.

So no, when using EJBs, you cannot inject the implementation, only the interface. If you really want to do this, I would move away from EJBs.

来源：https://stackoverflow.com/questions/34411371/is-it-possible-to-inject-ejb-implementation-and-not-its-interface-using-cdi