[FIXED] JSF provide very basic REST get method

Issue

Is there a way to have a doGet method in a @ManagedBean and define a URL on which this bean will react.

I am using JSF and want to provide a really basic feed, but for this I need to react on a get request.

I wrote it with normal servlets first, but now I noticed that I need information from another ManagedBean therefore I need a @ManagedProperty - hence JSF...

My questions:

• Is there a URLPattern annotation or similar?

• Is there a doGet method that is similar to the Servlet's doGet?

Solution

Assuming servlets...

If you're relying on the JSF context, the trick will be to get the FacesServlet to execute the code. The FacesServlet is responsible for creating and destroying the request context.

Here is the managed bean we want to invoke:

@ManagedBean @RequestScoped
public class Restlike {
  public void respond() {
   FacesContext context = FacesContext.getCurrentInstance();
   ExternalContext ext = context.getExternalContext();
   HttpServletResponse response = (HttpServletResponse) ext.getResponse();
   response.setContentType("text/plain; charset=UTF-8");
    try {
      PrintWriter pw = response.getWriter();
      pw.print("Hello, World!");
    } catch (IOException ex) {
      throw new FacesException(ex);
    }
    context.responseComplete();
  }
}

Here is the placeholder view that will execute the code. resty.xhtml:

<?xml version='1.0' encoding='UTF-8' ?>
<metadata xmlns="http://java.sun.com/jsf/core">
  <event type="preRenderView" listener="#{restlike.respond}"/>
</metadata>

Hitting resty.faces doesn't look very RESTful, but it is trivial to handle with a filter:

@WebFilter("/rest/*")
public class RestyFilter implements Filter {
  @Override
  public void doFilter(ServletRequest request, ServletResponse response,
                       FilterChain chain) throws IOException, ServletException {
    request.getRequestDispatcher("/resty.faces").forward(request, response);
  }

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {}

  @Override
  public void destroy() {} 
}

The resultant URL will look something like http://host/context/rest

---

This solution is a bit of a hack and only applicable to servlet environments. A better approach might be to add a custom ResourceHandler but I haven't spent much time investigating that part of the API.

Answered By - McDowell
Answer Checked By - Terry (JavaFixing Volunteer)