How do I filter all incoming requests and not just ones mapped to servlets?

I am toying around with embedded Jetty and I am wondering why my filter only intercepts /hi and not any other incoming request. Here is my example case:

Without Filter:

lo开发者_开发问答calhost:8080/hi
=> "Hello"
localhost:8080/foo
=> 404

With Filter:

localhost:8080/hi
=> "Hello from filter"
localhost:8080/foo
=> 404

I would expect the last 404 to return "Hello from filter". What am I missing?

Server server=new Server(8080);

ServletContextHandler context=
    new ServletContextHandler(ServletContextHandler.SESSIONS);

context.setContextPath("/");
context.addFilter(DispatchFilter.class,"/*",1);
context.addServlet(HelloServlet.class,"/hi");

server.setHandler(context);
server.start();
server.join();

To further clarify, my example is just a simplified representation of what I want to do. My intention is to have the DispatchFilter intercept every request. If a certain criteria is not met, then it should move on, otherwise return something derived from the request path.

---

From javax.servlet.Filter.doFilter()

The doFilter method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.

The key part here is the bit about the "end of the chain". Since /foo doesn't match an actual resource, the filters are not executed.

You can work around this by adding a default servlet:

context.addServlet(org.mortbay.jetty.servlet.DefaultServlet, "/");

Now all your requests have a valid endpoint and your filter will be executed.