Question

I want to delivered the URL of a servlet (MyServlet.java) to a java class (Test.java). Test.java is located in a Project.jar in folder lib of WEB-INF. So I have tried to pass the Servlet URL to Test.java

    import projct.Test;

    public class MyServlet extends HttpServlet {

        @Override
        public void init() throws ServletException {..}                

        @Override
        public void destroy() {..}

        @Override
        protected void doGet(HttpServletRequest request,
                HttpServletResponse response)
                throws ServletException, IOException {
            processRequest(request, response);
        }

        @Override
        protected void doPost(HttpServletRequest request,
                HttpServletResponse response)
                throws ServletException, IOException {
            processRequest(request, response);
        }

        protected void processRequest(HttpServletRequest request,
                HttpServletResponse response)
                throws ServletException, IOException {

             new Test().setServleturl(request.getRequestURL().toString());
             request.getRequestDispatcher("/index.html").forward(request, response);

        }
    }

The Test.java class looks like this:

    public class Test {
        private static String var;

        public static String getVar() {
            return var;
        }

        public static void setVar(String var) {
            Test.var = var;
        }    
    }

After Diployment is the value of var still null.

What am I doing wrong?
And how can you write the URL from MyServlet.java in var from Test.java?

Answer 1

I assume that setServleturl() is in fact setVar(), because it wouldn’t compile.

Of course it’s null after deployment. processRequest() is only called when a request… is processed. Make an HTTP request to your servlet, and the code will be executed.

That said, what you have there seems like a really bad idea, and it’s not thread-safe (setVar() and getVar() should be synchronized). Moreover, these methods should be called using Test.setVar(), and not new Test().setVar(), since they’re static methods. What are you trying to achieve?

EDIT: it seems the problem is to read files from WEB-INF at deployment time. To do that, use a ServletContextListener, and in its contextInitialized() method, get the servlet context from the event, and call servletContext.getResourceAsStream("/WEB-INF/theFileToLoad").