Jetty, doFilter method not getting called

Question

I have set up an embedded Jetty server with a filter to add some headers to every request.

MainHandler mainHandler = new MainHandler();
        ServletContextHandler servletContextHandler = new ServletContextHandler(ServletContextHandler.NO_SESSIONS);
        servletContextHandler.setContextPath("/application");
        servletContextHandler.setHandler(mainHandler);
        servletContextHandler.setAllowNullPathInfo(true);
        servletContextHandler.addFilter(MyFilter.class, "/*", EnumSet.of(DispatcherType.REQUEST, DispatcherType.INCLUDE, DispatcherType.FORWARD));

Mainhandler is the class which processes the requests. The init() method of the filter is called, but not the doFilter() Method thus my filter is not applied. I tried it with "/application/something".

Can anybody help me please?

Answer 1

Don't mix Handlers and ServletContextHandler's like that.

That's not what the ServletContextHandler.setHandler(Handler) is for.

Change your MainHandler to extend from HttpServlet and add it to the ServletContextHandler.addServlet() .

This is because ServletContextHandler.setHandler() is for the management of things outside of the ServletContext and the specific request chain (such as session management, security management, gzip encoding management, request logging management, etc), not for actually processing a request and producing a response within that ServletContext .

Answer 2

Look at this example of the official documentation:

package org.eclipse.jetty.embedded;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHandler;

public class MinimalServlets
{
    public static void main( String[] args ) throws Exception
    {
        // Create a basic jetty server object that will listen on port 8080.
        // Note that if you set this to port 0 then a randomly available port
        // will be assigned that you can either look in the logs for the port,
        // or programmatically obtain it for use in test cases.
        Server server = new Server(8080);

        // The ServletHandler is a dead simple way to create a context handler
        // that is backed by an instance of a Servlet.
        // This handler then needs to be registered with the Server object.
        ServletHandler handler = new ServletHandler();
        server.setHandler(handler);

        // Passing in the class for the Servlet allows jetty to instantiate an
        // instance of that Servlet and mount it on a given context path.

        // IMPORTANT:
        // This is a raw Servlet, not a Servlet that has been configured
        // through a web.xml @WebServlet annotation, or anything similar.
        handler.addServletWithMapping(HelloServlet.class, "/*");

        // Start things up!
        server.start();

        // The use of server.join() the will make the current thread join and
        // wait until the server is done executing.
        // See
        // http://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html#join()
        server.join();
    }

    @SuppressWarnings("serial")
    public static class HelloServlet extends HttpServlet
    {
        @Override
        protected void doGet( HttpServletRequest request,
                              HttpServletResponse response ) throws ServletException,
                                                            IOException
        {
            response.setContentType("text/html");
            response.setStatus(HttpServletResponse.SC_OK);
            response.getWriter().println("<h1>Hello from HelloServlet</h1>");
        }
    }
}