public void doPost(HttpServletRequest request, 
    HttpServletResponse response)
    throws ServletException, IOException {
    
    String userName = request.getParameter("userName");
    String password = request.getParameter("password");
    if (login(userName, password)) {
      RequestDispatcher rd =
        request.getRequestDispatcher("AnotherServlet");
      rd.forward(request, response);
    }
    else {
      sendLoginForm(response, true);
    }
  }