Question

I want to make a web application using JSF 2.0 and Hibernate. I want to log exceptions in a data base[Asynchronously].

How can I do this?

Answer 1

The information you give in your question is a bit meager really, but I’ll give it a shot anyway.

Limiting exception logging to those that occur during request processing (as per your comment), your first step would be to install a Servlet Filter:

@WebFilter(filterName="exceptionHandler", urlPatterns="/*")
public class ExceptionHandler extends HttpFilter {

    @Override
    public void doFilter(HttpServletRequest request, HttpServletResponse response, HttpSession session, FilterChain chain) throws ServletException, IOException {

        try {
            chain.doFilter(request, response);
        } catch (Exception e) {
            // ... handle exception here
        }
    }
}

If you already have other filters installed, you’ll probably need a web.xml to tune the order in which they are called.

The next step is to do the asynchronous persisting to a DB. Here it depends on what stack you are using beyond JSF and Hibernate. For instance, Java EE has a convenient @Asynchronous annotation here, while in Spring it’s @Async. In general JSF is most often combined with Java EE, but people saying they’re using Hibernate instead of JPA typically tend to be on Tomcat.

For Java EE you would inject an EJB in the Filter, with the EJB using JPA (possibly Hibernate) and the mentioned @Asynchronous annotation:

Filter:

@WebFilter(filterName="exceptionHandler", urlPatterns="/*")
public class ExceptionHandler extends HttpFilter {

    @EJB
    private ExceptionPersister exceptionPersister;

    @Override
    public void doFilter(HttpServletRequest request, HttpServletResponse response, HttpSession session, FilterChain chain) throws ServletException, IOException {

        try {
            chain.doFilter(request, response);
        } catch (Exception e) {
            exceptionPersister.persist(e);
        }
    }
}

EJB:

@Stateless
public class ExceptionPersister {

    @PersistenceContext
    private EntityManager entityManager;

    @Asynchronous
    public void persist(Exception exception) {
        // use entityManager to persist exception in your
        // specific way.
    }
}