LoginServlet

package com.mvc.controlle;

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

import com.mvc.bean.*;

import com.mvc.dao.*;
/**
 * Servlet implementation class Servlet
 */
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		 	String userNameInput = request.getParameter("user");
	        String passwordInput = request.getParameter("pwd");

	        StaffBean loginBeanInput = new StaffBean(); // Bean classes are efficiently used to access user information wherever required in the application.
	        loginBeanInput.setName(userNameInput);
	        loginBeanInput.setPwd(passwordInput);

	        StaffDao loginDao = new StaffDao();
	        
	        String userValidate = loginDao.authenticateUser(loginBeanInput);

	        if(userValidate.equals("SUCCESS")){
	            System.out.print("SUCCESSyes");
	            request.setAttribute("userNameInput", userNameInput); //with setAttribute() you can define a "key" and value pair so that you can get it in future using getAttribute("key")
	            request.getRequestDispatcher("/KMGP.jsp").forward(request, response);//RequestDispatcher is used to send the control to the invoked page.
	        }

	        else{
	            System.out.print("SUCCESSno");
	            request.setAttribute("errMessage", userValidate); // Here the error message returned from function has been stored in a errMessage key.
	            request.getRequestDispatcher("/login.jsp").forward(request, response);//forwarding the request
	        }
	}

}