login controller.servlet file.. (good coding stuff for reference)

package com.tcs.ilp.controller;

import java.io.*; import java.util.*; import com.tcs.ilp.model.*; import java.sql.*; import java.io.IOException; 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 javax.servlet.RequestDispatcher; /** * Servlet implementation class LoginController */ public class LoginController extends HttpServlet { private static final long serialVersionUID = 1L;

/**
 * @see HttpServlet#HttpServlet()
 */
public LoginController() {
    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
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub

  try{

  ArrayList<String> x=new ArrayList<String>();

  String uname=request.getParameter("uname");

  System.out.println(uname);
  String upass=request.getParameter("upass");
  System.out.println(upass);

  HttpSession session=request.getSession();
  session.setAttribute("uname",uname);
  session.setAttribute("upass",upass);

  Connection conn=Create_Connection.conOpen(); 
  System.out.println("Hello");
  int u=LoginDAO.chk_user(conn,uname,upass);
  System.out.println(u);
  if(u==1)
  {
     System.out.println("yaya");
     x=LoginDAO.getDetails(conn,uname,upass);    

     String id=x.get(0);
     String role=x.get(1);

     //System.out.println(x.get(0));
     //System.out.println(x.get(1));

    session.setAttribute("id", id);
    session.setAttribute("role", role);


    if(role.equals("retailer"))
    {
        session.setAttribute("id", id);
        session.setAttribute("role", role);
        RequestDispatcher disp = request.getRequestDispatcher("Retailer_home.jsp");
        disp.forward(request,response);
    }

    if(role.equals("manager"))
    {
        session.setAttribute("id", id);
        session.setAttribute("role", role);
        RequestDispatcher disp = request.getRequestDispatcher("manager_home.jsp");
        disp.forward(request,response);
    }    

    if(role.equals("admin"))
    {
        session.setAttribute("id", id);
        session.setAttribute("role", role);
        RequestDispatcher disp = request.getRequestDispatcher("header.html");
        disp.forward(request,response);
    }
  }
  }
  catch(Exception e) {}
}

}