Hello Users,
I have been learning the Prepared Statements in Java which is a newer and better way of entering details into the Database.
Have been getting problems with the insertion: NullPointerException and still don't know where I am going wrong.
Please Assist me in Solving the Issue.
Code Below:
Registration Method:
public void SignUser(String Username , String HashWord)
throws ClassNotFoundException , SQLException , Exception , NullPointerException
{
String Password = "";
MessageDigest MD5 = MessageDigest.getInstance("MD5");
MD5.update(Password.getBytes());
BigInteger Hash = new BigInteger(1 , MD5.digest());
HashWord = Hash.toString(16);
Connection SQLConnector = ConnectToTheDatabase();
PreparedStatement PS = null;
String RegistrationQuery = "INSERT INTO trial (Username , HashWord) VALUES ('" + Username + "' , '" + HashWord + "')";
PS = SQLConnector.prepareStatement(RegistrationQuery);
PS.executeUpdate();
}
Registration Servlet
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package User;
import DataAccessObject.DAO;
import DataAccessObject.DAO_Interface;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.SQLException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
*
* @author SaguWesker
*/
public class SignUp extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try
{
RequestDispatcher rd = request.getRequestDispatcher("Relay");
DAO_Interface Dao = DAO.getDAOInterface();
Dao.SignUser(request.getParameter("Username"), request.getParameter("HashWord"));
HttpSession Session = request.getSession();
String Username = request.getParameter("Username");
Session.setAttribute("Username", request.getParameter("Username"));
RequestDispatcher sign_up_successful = request.getRequestDispatcher("index.jsp");
sign_up_successful.forward(request, response);
}
catch (ClassNotFoundException CNFE)
{
System.out.println(CNFE);
}
catch (SQLException SQLE)
{
System.out.println(SQLE);
}
catch (Exception E)
{
E.printStackTrace();
}
}
//finally
//{
//out.close();
//}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
