Thread: User Login System Program.

import javax.swing.*;
import java.awt.event.*;
import java.sql.*;
import java.awt.*;
 
public class CONNECT implements ActionListener {
 
    Connection con;
    Statement st;
    ResultSet rs;
 
    JFrame f;
    JLabel user;
    JLabel pass;
    JButton b;
    JButton b1;
    JTextField t;
    JTextField t1;
    int count;
 
   public CONNECT(){
       connect();
       frame();
   }
    public void connect(){
        try{
        Class.forName("com.mysql.jdbc.Driver");
        con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test1","root","");
        st= con.createStatement();
 
 
    }catch(Exception e){
 
    }
    }
    public void frame(){
 
            f=new JFrame("User Login");
            f.setSize(600,400);
            f.setVisible(true);
            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
            user = new JLabel("UserName");
            pass = new JLabel("Password");
            b = new JButton("Login");
            b1=new JButton("Cancel");
            t=new JTextField(10);
            t1=new JTextField(10);
            JPanel p=new JPanel();
            p.add(user);
            p.add(t);
            p.add(pass);
            p.add(t1);
            b.addActionListener(this);
            p.add(b);
            b1.addActionListener(this);
            p.add(b1);
 
            f.add(p);
 
    }
               public void actionPerformed(ActionEvent e)
               {
                   if(e.getSource()==b){
                       call();
 
 
             }   
                   if(e.getSource()==b1){
                       JOptionPane.showMessageDialog(null,"Thank You!");
                   }
 
            }
 
            public void call(){
                try{
                   String use=t.getText();
                   String pas=t1.getText();
                   String query="select * from persons1";// where user ='"+user+"'and pass ='"+pass+"'";
                   rs=st.executeQuery(query);
                   count =0;
                   while(rs.next()){
                       String uname=rs.getString("user");
                       String ps = rs.getString("pass");
 
                       if(uname.equalsIgnoreCase(use)&&ps.equalsIgnoreCase(pas))
                       {
                          count ++;
                       }
                   }
 
 
 
                   }catch(Exception ex){
 
               }
                if (count ==1){
                    JOptionPane.showMessageDialog(null,"User Found And Access Granted");
                }
                else if(count >1){
                    JOptionPane.showMessageDialog(null,"Double Accounts Not Allowed");
                }
                else
                    JOptionPane.showMessageDialog(null, "User Not Found.");
            }
       public static void main(String[] args) {
        new CONNECT();
       }
 
 
}

In the program the "Login" button is not performing as expected.It is not reading data from mySQL database.I use XAMPP control panel.The Button is expected to take the data from the database which has a table named "persons1"...In this table I have to fields 1.user 2.pass...the button should take in the data from there and check from the data entered by the user.

Done editing.I hope now its legible.

There are two text fields.First is UserName and the next is Password all this in . The user enters his/her details in the text fields. In the Login button I am calling call(). In this method I am reading the text entered by the user and storing it in variables 'use' and 'pas' respectively. Then inside a while loop I am reading from mySQL database and comparing the retrieved data with the data stored in 'use' and 'pas'. If it matches then count is getting increased. Then outside in an If loop I am checking if count == 1 then I am printing "User Found". I hope this answer your question.

This is what I am getting.

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(URLClassLoader.java: 366)
at java.net.URLClassLoader$1.run(URLClassLoader.java: 355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:4 24)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 57)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:190)
at CONNECT.connect(CONNECT.java:27)
at CONNECT.<init>(CONNECT.java:22)
at CONNECT.main(CONNECT.java:108)
java.lang.NullPointerException
at CONNECT.call(CONNECT.java:81)
at CONNECT.actionPerformed(CONNECT.java:66)
at javax.swing.AbstractButton.fireActionPerformed(Abs tractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed (AbstractButton.java:2341)
at javax.swing.DefaultButtonModel.fireActionPerformed (DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultB uttonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseRe leased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.jav a:6505)
at javax.swing.JComponent.processMouseEvent(JComponen t.java:3321)
at java.awt.Component.processEvent(Component.java:627 0)
at java.awt.Container.processEvent(Container.java:222 9)
at java.awt.Component.dispatchEventImpl(Component.jav a:4861)
at java.awt.Container.dispatchEventImpl(Container.jav a:2287)
at java.awt.Component.dispatchEvent(Component.java:46 87)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(C ontainer.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:4422)
at java.awt.Container.dispatchEventImpl(Container.jav a:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719 )
at java.awt.Component.dispatchEvent(Component.java:46 87)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:735)
at java.awt.EventQueue.access$200(EventQueue.java:103 )
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:708)
at java.awt.EventQueue$4.run(EventQueue.java:706)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 705)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:91)

--- Update ---

Thanks to you. I was able to solve the problem. Thanks a lot.