JDBC Java Application not working

[Dene Lamprecht]

Hi people

I would appreciate some help, I am building a Java Application using Netbeans 5.5 and a Ms SQL Server 2000 database. It is a program for a Video Store.
I am busy with an edit interface where the user can add a genre or movie or delete a movie from the database. But I need to make the user enter a username and password before any editing can be done.

I've created a JtextField for the USERNAME and a JPasswordField for the PASSWORD. I am trying to match the USERNAME and PASSWORD against the database.
The program does not return any errors, but if I press Login nothing happens. This is the part for the Login Screen:

/*
 * UserLogin.java
 *
 * Created on September 15, 2009, 11:34 AM
 */

package videostoreprogram;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.JOptionPane;

/**
 *
 * @author  Woudene
 */
public class UserLogin extends javax.swing.JFrame {
    
    /** Creates new form UserLogin */
    public UserLogin() {
        initComponents();
    }
    
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">                          
    private void initComponents() {
        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        tfUser = new javax.swing.JTextField();
        pfPass = new javax.swing.JPasswordField();
        jButton1 = new javax.swing.JButton();
        jLabel4 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
        setTitle("User Login");
        jLabel1.setText("Enter Username & Password to continue.");

        jLabel2.setText("USERNAME:");

        jLabel3.setText("PASSWORD:");

        jButton1.setText("LOGIN");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        org.jdesktop.layout.GroupLayout jPanel1Layout = new org.jdesktop.layout.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(org.jdesktop.layout.GroupLayout.TRAILING, jPanel1Layout.createSequentialGroup()
                .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.TRAILING)
                    .add(jPanel1Layout.createSequentialGroup()
                        .addContainerGap()
                        .add(jLabel4, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 199, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                    .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.TRAILING)
                        .add(jPanel1Layout.createSequentialGroup()
                            .addContainerGap()
                            .add(jLabel1))
                        .add(jPanel1Layout.createSequentialGroup()
                            .add(62, 62, 62)
                            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.TRAILING)
                                .add(jLabel2)
                                .add(jLabel3))
                            .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                                .add(pfPass, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, 144, Short.MAX_VALUE)
                                .add(jPanel1Layout.createSequentialGroup()
                                    .add(10, 10, 10)
                                    .add(jButton1))
                                .add(tfUser, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, 144, Short.MAX_VALUE)))))
                .add(65, 65, 65))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(jPanel1Layout.createSequentialGroup()
                .add(36, 36, 36)
                .add(jLabel1)
                .add(31, 31, 31)
                .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(jLabel2)
                    .add(tfUser, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(pfPass, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                    .add(jLabel3))
                .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                .add(jButton1)
                .add(32, 32, 32)
                .add(jLabel4, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 22, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(53, Short.MAX_VALUE))
        );

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(jPanel1, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(jPanel1, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
        );
        pack();
    }// </editor-fold>                        

String data = "jdbc:odbc:VideoStore";
    
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        try{
		Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
		Connection conn = DriverManager.getConnection(data, "", "");
		Statement st = conn.createStatement();
		ResultSet rs = st.executeQuery("SELECT users_name, users_password FROM Users");
        
                while (rs.next()){
			String un = tfUser.getText();
			char[] pass = pfPass.getPassword();
        		String pw = new String(pass);
			
			if (un.equals(rs.getString("users_name"))) {    
				if (pw.equals(rs.getString("users_password"))) { 
					dispose();
				} else {
					JOptionPane.showMessageDialog(null, "Password did not match username!", "Warning...", JOptionPane.WARNING_MESSAGE);
				}
                        } else {
					JOptionPane.showMessageDialog(null, "Username did not match the database", "Warning...", JOptionPane.WARNING_MESSAGE);
			}
		}
        } catch(SQLException d) {
                dispose();
        } catch(ClassNotFoundException f) {
                dispose();
	}

    }      
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new UserLogin().setVisible(true);
            }
        });
    }
    
    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPasswordField pfPass;
    private javax.swing.JTextField tfUser;
    // End of variables declaration                   
    
}    

From part:

String data = "jdbc:odbc:VideoStore";

is where the action happens for the login.

I know it is not very secure but this is only a project for school, I just need it to be able to login.

Thank you in advance

[Jeanne Boyarsky]

Dene,
You are "swallowing" any database exceptions that occur:

  } catch(SQLException d) {  
   dispose();  
 }

Can you try adding "d.printStackTrace()" to see what is the actual database error message?

[Dene Lamprecht]

Thank you for the reply Jeanne, I have changed that specific piece of code to:

 } catch(SQLException d) {
                d.printStackTrace();
          } catch(ClassNotFoundException f) {
                f.printStackTrace();
	  }  

But still when I run the program and click the LOGIN button I get no exception or any printout. If I can at least get an error I can try to fix it.

[Ulf Dittmer]

Is the jButton1ActionPerformed method being called?

[Dene Lamprecht]

Hi Ulf I am not sure what you mean, I have added an event ActionPerformed to jButton1 and written the database connection code inside the event.

Is that the correct way?

[Ulf Dittmer]

Well, it doesn't matter what's inside the action listener if it's not being run for some reason :-) Put a System.out.println statement at the beginning of the jButton1ActionPerformed method to check if it's actually being called.

[Somnath Mallick]

Is the variable "data" be static if its in outside any method (...i mean, if its a variable declared at class level)! Although your middle part of the code is a bit complicated to look at.
Few things:

while (rs.next())
{  
        String un = tfUser.getText();  
        char[] pass = pfPass.getPassword();  
        String pw = new String(pass);  

No need to retrieve it in every loop. Putting un, pass and pw outside the loop would be better.

Also modify your SQL query to something like:

SELECT users_name, users_password FROM Users where user_name=un and password=pw.

If it returns a row in a ResultSet, then the user name, password exists and this would make the redundant looping go away make would optimize the code a little.