loginaction.java

Simple login example for jsp beginner...

package us.souther.simple.login;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

public class LoginAction implements Action{
    public void perform(HttpServletRequest  request,
                        HttpServletResponse response)throws ServletException, IOException{

        String      username = request.getParameter("username");
        String      password = request.getParameter("password");
        HttpSession session  = request.getSession();


        //
        // If we came here from the accessFilter, we will already have a loginBean.
        LoginBean   loginBean; 
        loginBean = (LoginBean)session.getAttribute("loginBean");
        if(null == loginBean){
            loginBean = new LoginBean();
        }

        //
        // If the form hasn't been submitted, just show the page.
        //
        if(null == request.getParameter("enter_button")){
            request.getRequestDispatcher("/WEB-INF/jsps/login.jsp").forward(request, response);
            return;
        }

        // 
        // Validate Login
        //
        if(null == username || "".equals(username) ||
           null == password || "".equals(password)){
            loginBean.setErrorMessage(
                "Username and password are required fields");
            loginBean.setUsername(username);

            session.setAttribute("loginBean", loginBean);
            request.getRequestDispatcher("/WEB-INF/jsps/login.jsp").forward(request, response);
            return;
        }

        // 
        // Add the userBean to session.
        //
        UserBean userBean = new UserBean();
        userBean.setUsername(username);
        session.setAttribute("userBean", userBean);

        //
        // See what page the user attempted to view.
        // Send them to that page or the menu if empty.
        //
        String requestedUrl = loginBean.getRequestedUrl();
        if(null == requestedUrl){
            requestedUrl = request.getContextPath() + "/index.html";
        }

        //Login bean is no longer needed.
        session.removeAttribute("loginBean");

        // redirect user to original destination.
        response.sendRedirect(requestedUrl);
    }
}