Accessibility of a servlet class from within an external web.xml file

Question

I have two web applications.But only one among them includes Java servlet class.I want to access that servlet class from within the web.xml file of other application.Is it possible?.If yes,How will be it possible?.

Answer 1

You can't do that in the web.xml. You can however create a new servlet which in turn redirects/forwards the request to the servlet of the other webapplication. Redirecting is easy, just let the URL point to the particular servlet.

response.sendRedirect("/otherwebapp/theservlet");

Forwarding requires a bit more work. This is by default not possible due to security restrictions. First you need to configure the servletcontainer to enable cross context access between the webapplications in question. It's unclear which one you're using, so here's just a Tomcat targeted example so that you understand in what direction you should look for your own servletcontainer: for the both webapps, you need to set the crossContext attribute of the <Context> element to true:

<Context crossContext="true">

This way you can obtain the other context by ServletContext#getContext() inside a servlet:

ServletContext othercontext = getServletContext().getContext("/otherwebapp");

Finally you can forward the request through it as follows:

othercontext.getRequestDispatcher("/theservlet").forward(request, response);