import java.io.*;

import java.sql.*;

import javax.servlet.*;

import javax.servlet.http.*;



public class Login extends HttpServlet{
	
	public String validateUser(String inputUserid, String inputPwd) 
   throws SQLException, ClassNotFoundException{
	String returnString = null;
	String dbUserid = ""; // Your Database user id
	String dbPassword = "" ; // Your Database password
	Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
    Connection con = DriverManager.getConnection("jdbc:odbc:teste",
						dbUserid ,dbPassword );
	Statement stmt = con.createStatement();
	String sql= "select USERID from USER where USERID = '" + 
		   inputUserid + "' and PASSWORD = '" + inputPwd +"' ;" ; 
	ResultSet rs = stmt.executeQuery(sql);
	if (rs.next())
	{
	  returnString = rs.getString("USERID");
	}
	stmt.close();
	con.close();
	return returnString ;
}

  public void doPost(HttpServletRequest req, HttpServletResponse res)
			throws ServletException,IOException{


  String userId = req.getParameter("userId");
  String password = req.getParameter("password");

/************************************************************
** call a method to validate the password which will return the 
** User Name for authorized users and null string for un-authorised. 
**********************************************************/
  String uName = validateUser(userId, password);
  
// if uName is null .. user is not authorized.

  if (uName == null)
       {

	PrintWriter ot = res.getWriter();
        ot.println(" Please verify the Userid and password");
        ot.close();
       }
  else
       {

   // So the user is valid let's create a seesion    // for this user.

      HttpSession userSession = req.getSession(true);

   // put the user name session variable.

      userSession.setAttribute("userName", uName);

  // now we need to transfer the control to welcome.jsp

      RequestDispatcher rd = 
	getServletContext().getRequestDispatcher("/welcome.jsp");

      if (rd != null)
         {
	  rd.forward(req,res);
         }

       }


  }// end of doPost
  
  


}// end of servlet class