Question

jsp file which contains username & password which is processed at LoginServlet…this servlet does the validation in Access db. but i m getting error

if username & password matches with the access db then the page redirect to flat_status.jsp

can any1 help me out..

    package Validate;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class LoginServlet extends HttpServlet{

    @Override
    public void init(ServletConfig config) throws ServletException
    {
        super.init(config);
            try
        {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        }
        catch (Exception ex)
        {
            System.out.println("Initialize connector string");
        }
        }
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
    {
                Connection conn;
    Statement st;
    ResultSet rs;
    PrintWriter pw = response.getWriter();
        String userName = request.getParameter("username");
    String password = request.getParameter("password");
        HttpSession session = request.getSession(true);
        response.setContentType("text/html");
            try 
            {
                conn=DriverManager.getConnection("jdbc:odbc:FBS");
                st=conn.createStatement();
                rs=st.executeQuery("select UserName,Password from user_login where UserName='"+userName+"' and Password='"+password+"'");
                while(rs.next())
                {
                    session.setAttribute("USerName",userName);
                    RequestDispatcher dispatch=request.getRequestDispatcher("/flat_status.jsp");
                    dispatch.forward(request, response);
                }
            st.close();
            rs.close();
            conn.close();
            } 
            catch (SQLException ex) 
            {
                  pw.println(ex);  
            }
        }

        }

Here is Exception i m getting in Browser window

java.sql.SQLException: [Microsoft][ODBC Microsoft Access Driver] Data type mismatch in criteria expression.

Answer 1

Always use PreparedStatement and Password is reserved keyword in Ms-Access.

  boolean userFound=false;

  conn=DriverManager.getConnection("jdbc:odbc:FBS");
  String sql="select [UserName],[Password] from user_login 
                            where [UserName]=? and [Password]=?";
  PreparedStatement st=conn.prepareStatement(sql);
  st.setString1(1,userName);
  st.setString1(2,password);
  rs=st.executeQuery();

  if(rs.next())
   {
    userFound=true;
   }
  st.close();
  conn.close();

 if(userFound)
  {
  }