Call a function in servlet from java class.

Question

Hi,
I am implementing a client/server technology by trying to convert a java desktop client into Browser based. As part of user authetication the only way I know that a username /password does not match is from the servers message as i dont have documentation of the backend servers database.
Here is a fucntion which receives lines form server.
public class ServerComm{
public synchronized void receiveMessage(String  serverMessage){
if (serverMessage.equals("Login-Fail"))// Login-Fail is message from server if login fails
LoginHandler.loginFail()//Login Handler is a servlet
return
}The Login Handler servlet is as follows.
public class LoginHandler extends HttpServlet {
    /** Initializes the servlet.
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
    /** Destroys the servlet.
    public void destroy() {
    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
    protected synchronized void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
//some expressions.       
   //this is reached if login fails.
    public static void  loginFail(){
        HttpServletResponse response;
    //redirected to wronglogin web page.  
  response.sendRedirect("/mCVW/wronglogin.jsp");
    /** Handles the HTTP <code>GET</code> method.
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    /** Handles the HTTP <code>POST</code> method.
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
   }Now there is problem in loginFail() method in LoginHandler servlet does not work with the type of response decleration . I need some assistance from any one to make this work or propose a better solution for determining the user authetication with the restriction i have.
Thank you.

Answer 1

hmm...I haven't tried this before...but does this work by any chance?
In your ServerComm class, create new HttpServletRequest and Response objects and get a RequestDispatcher object from request.
Eg : if (serverMessage.equals("login-fail"){
HttpServletRequest request = new HttpServletRequest ();
HttpServletResponse response = new HttpServletResponse ();
request.setAttribute("function_id", "loginFail");
RequestDispatcher dispatcher = request.getRequestDispatcher("http://servername:port/ServletName");
//give the complete path of your servlet
dispatcher.forward(request, response);
and in your Servlet, get this function_id and if its loginFail, redirect it to wronlogin.jsp...
public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
String function_id = request.getAttribute("function_id");
if(function_id.equalsIgnoreCase("loginFail"))
//forward to ur jsp
getServletConfig().getServletContext().getRequestDispatcher(wronlogin.jsp").forward(request, response);
}