Servlet Does not write to database

[jokwara]

I am pretty new to Java Servlets and I Need to be pointed to the right direction. I am writing a login servlet which somehow does not appear to be querying the database.

Please some directions as to what I am doing wrong.

Thanks
Jonas

package WEBp;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
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;


public class AuthenticateServlet extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
processRequest(request, response);
}


protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
RequestDispatcher dispatcher ;
PrintWriter out = response.getWriter();
HttpSession UserSession = request.getSession();
String username = request.getParameter("username");
String password = request.getParameter("password");
String category = request.getParameter("category");
try{

response.setContentType("text/html");

Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection con=DriverManager.getConnection("jdbc:mysql://192.168.1.22/StudentGradeManagement", "jokwara", "chi4me");
Statement statement =con.createStatement();
ResultSet results = statement.executeQuery("select username, password, category from authenticate where username =' "+username+" ' ");

while(results.next()){
String realUser = results.getString(username);
String realPassword = results.getString(password);
String realCategory = results.getString(category);


if( ( username.equals(realUser) ) || ( realCategory.equals("student") ) || (password.equals(realPassword)) ) {
UserSession.setAttribute("realUser", realUser);
response.sendRedirect("studentView.jsp");
dispatcher = request.getRequestDispatcher("studentView.jsp");
dispatcher.forward(request, response);

}
else if (( username.equals(realUser) ) || (password.equals(realPassword)) || ( realCategory.equals("staff" ) ) ){
UserSession.setAttribute("realUser", realUser);
dispatcher = request.getRequestDispatcher("staffView.jsp");
dispatcher.forward(request, response);
}

else if (( username.equals(realUser) ) || (password.equals(realPassword)) || ( realCategory.equals("teacher" ) ) ){
UserSession.setAttribute("realUser", realUser);
dispatcher = request.getRequestDispatcher("teacherView.jsp");
dispatcher.forward(request, response);
}

else if ( ( realCategory.equals(" ") ) || ( realUser.equals("") ) || (realPassword.equals("")) ){
response.sendRedirect("registerlogin.html");
}
}

}
catch(Exception e){
System.out.println(e);
}
}
}

[Khalid Ali]

are u getting any errors? if so pls post those, if no errors then chances are there is nothing to write