How to redirect from one servlet to another by using tricky redirection?

Question

If I have two servlets:

@WebServlet (urlPatterns = {"/s1"})
public class Servlet1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
    throws ServletException, IOException {

        Map<String, Integer> map = new HashMap<String, Integer>();
        map.put("A", 100);
        map.put("B", 200);
        map.put("C", 300);

        req.setAttribute("map", map);
        getServletContext().getRequestDispatcher("Servlet2").forward(req, resp);
    }
}

public class Servlet2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
    throws ServletException, IOException {
        Map map = (Map) req.getAttribute("map");

        for (Object o : map.values()) {
            System.out.println(o);
        }
    }
}

How can I make redirect between them? And which path I need to use in my getRequestDispatcher method? And one more condition - Servlet2 must be without any mapping in annotations or in web.xml.

Answer 1

Servlet2 must be without any mapping in annotations or in web.xml.

Then you cannot use HttpServletRequest#getRequestDispatcher(String), which is a container managed method that checks those mappings.

That condition is ridiculous and makes no sense. If you aren't going to use the Servlet container, don't make a Servlet. Make a service class that performs the actions you need. You don't need to make everything a Servlet.

Your only (ridiculous) alternative is to instantiate Servlet2 and explicitly invoke its doGet method.