Using servlet to log user out in Java EE application

Question

Using this answer I tried to logout.

Servlet Code:

@WebServlet(name = "LogoutServlet", urlPatterns = {"/logout"})
public class LogoutServlet extends HttpServlet {
    private static org.apache.log4j.Logger logger = org.apache.log4j.Logger.getLogger(user.class);

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Destroys the session for this user.
        if (request.getSession(false) != null) {
            request.getSession(false).invalidate();
        }

        // Redirects back to the initial page.
        logger.warn(request.getContextPath());
        response.sendRedirect(request.getContextPath());

    }
}

View Code:

<h:form>
      <h:commandButton value="Logout" action="/logout"/>
</h:form>

Error:

Unable to find matching navigation case with from-view-id '/Admin/appManager.xhtml' for action '/logout' with outcome '/logout'

I don't think servlet is taking the request with "/logout" url pattern. what have I done incorrect?

SJuan76 · Accepted Answer · 2012-07-24 05:52:51Z

1

In JSF, the action is not the URL of the next servlet to be called. Rather than that, it defines navigation rules either through faces-config or directly from the backing beans.

The message tells you that your app has no matching for an action logout from your .xhtml page.

I would do something like

<h:commandButton value="Logout" action="#{backingBean.logout()}"/>

where you have a ManagedBean BackingBean with the method logout() and which returns the URL to the "goodbye" address.

Note: If you want to do the operation from a servlet, you should use regular html tags (<a>, <button> instead of JSF components) to link to it.

answered Jul 24, 2012 at 5:52

SJuan76

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5 Comments

kinkajou Over a year ago

Is it fair to use single backing bean with logout method in all pages. I may have lot of pages and each page calling to same backing beans method

SJuan76 Over a year ago

Yes. In any page you can use multiple backing beans; either for data or actions. And reciprocally, you can use any bean from any page.

kinkajou Over a year ago

+1 helpful :) Can you provide simple example with <a> tag and servlet?

SJuan76 Over a year ago

Use the <a> tag as if it was plain HTML. In fact it is just the HTML tag.

SJuan76 Over a year ago

Just found about h:outputLink, to generate the link directly from JSF. Needed if you need to pass a parameter value through EL. marceloagustini.wordpress.com/2012/04/24/…

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