从JSF托管Bean调用JAX-RS Web服务

Question

I currently develop a Web application that can be accessed over HTTP by an Android application or a Web browser. Both user agents basically provide the same functionalities. The Android app calls RESTful Web Services built with JAX-RS/Jersey, while Web pages are Facelets backed by JSF managed beans. I thus consider that there are two types of possible entry points to the Web app. The Web services do all the necessary work (accessing the resources, performing the database operations within DAOs, etc.) and most importantly, they must act on their own. Therefore, they constitute an independent layer.

In order to reuse the code, is it a good practice to call a Web service from a managed bean? Are their life cycle compatible?

The idea is to inject the Resource object into the managed bean (with CDI, but not necessarily) and to call its methods programmatically . The Web service would act as a business delegate (?) to the underlying services.

I widely googled the question but I didn't get a clear answer. I saw some pieces of code where the managed bean invokes a Web service with its URL, but since all my components are located in a single server app, I don't see what prevents me from linking them directly .

Subsidiary question on error handling: I am also annoyed with the idea of catching WebApplicationExceptions from the Web service into my managed bean for returning error messages back to the view (with FacesMessage). My father always told me that I should never catch runtime exceptions...So, is there a good way to handle them correctly?

Answer 1

In this case, you would be better off having the business logic out from the Web Service into "some central shared code". Then, then web services and the managed beans would call into the shared code.

I've put the term "some central shared code" in quotes, as what you use depends on your runtime environment. If you're using a JavaEE container like Glassfish or JBoss, this sounds like a perfect use of EJB and stateless session beans (which are designed to ensure the resources are managed well). You could also use Spring Beans as the shared code and centralize the logic that way.

It all depends on what you find more comfortable from a development and production sense. But both support injection, so both the Web Service and JSF Managed Beans could have the services injected as any other resource.