Problems adding to database

Question

I'm making a chat program and I'm trying to use a database for all the users that are connected so the people chatting can see whos connected. Unfortunately, I can't get the usernaes to go into the database. I've tried the same code elsewhere and it works fine but in this program it won't add the names. My database is a MySQL database and has the name 'users' and the table is called 'connected' with 1 column called 'name'. I can get a window to pop up with the column heading at the top but no names will be added. It won't even add the "not good" string in my code... I'm not actually getting any sql errors, it just won't grab the names.
heres my relevant code:
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
     static final String DATABASE_URL = "jdbc:mysql://localhost/users?user=mike&password=blitz84";
userName = JOptionPane.showInputDialog(
            ClientGUI.this, "Enter user name:" );
         dUserName = userName;
         dUserName = "Not Good";
                          String input = dUserName;
                    String use = "use users"; 
                    try
                         Class.forName(JDBC_DRIVER);//load database driver class
                         conn = DriverManager.getConnection(DATABASE_URL);//establish connection to database
                         stat = conn.createStatement();//create statement for submitting information to the database
                         stat.executeUpdate(use);//ensures proper database is loaded
                         String query = "insert into connected values('"+input+"')";//string to enter data
                         stat.executeUpdate(query);//submits data to database
                         stat.close();//close connection
                    catch(Exception e)
                         System.out.println("Error at "+e);
                         e.printStackTrace();
                    }//end try and catch             

Answer 1

I tried it and it still didn't put anything in the database, here's my complete code, maybe that will help:
package com.deitel.messenger;
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import java.sql.*;
public class ClientGUI extends JFrame {
     //setting up the database for users
     static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
     static final String DATABASE_URL = "jdbc:mysql://localhost/users?user=mike&password=blitz84";
     String use = "use users";
     private Statement stat;
     private Connection conn;
   // JMenu for connecting/disconnecting server
   private JMenu serverMenu;
   // JTextAreas for displaying and inputting messages
   private JTextArea messageArea;
   private JTextArea inputArea;
   private JTextArea users;
   // JButtons and JMenuItems for connecting and disconnecting
   private JButton connectButton;
   private JMenuItem connectMenuItem;  
   private JButton disconnectButton;
   private JMenuItem disconnectMenuItem;
   private JMenuItem showUsers;
   // JButton for sending messages
   private JButton sendButton;
   // JLabel for displaying connection status
   private JLabel statusBar;
   // userName to add to outgoing messages
   private String userName;
   public String dUserName;
   // MessageManager for communicating with server
   private MessageManager messageManager;
   // MessageListener for receiving incoming messages
   private MessageListener messageListener;
   // ClientGUI constructor
   public ClientGUI(MessageManager manager)
      super( "Chat program of Splendor" );
      // set the MessageManager
      messageManager = manager;
      // create MyMessageListener for receiving messages
      messageListener = new MyMessageListener();
      // create Server JMenu     
      serverMenu = new JMenu ( "Server" );  
      serverMenu.setMnemonic( 'S' );
      JMenuBar menuBar = new JMenuBar();
      menuBar.add( serverMenu );
      setJMenuBar( menuBar ); 
      // create ImageIcon for connect buttons
      Icon connectIcon = new ImageIcon(
         getClass().getResource( "images/Connect.gif" ) );
      // create connectButton and connectMenuItem
      connectButton = new JButton( "Connect", connectIcon );
      connectMenuItem = new JMenuItem( "Connect", connectIcon ); 
      connectMenuItem.setMnemonic( 'C' );
      showUsers = new JMenuItem( "Show Users");
      showUsers.setMnemonic('U');
      // create ConnectListener for connect buttons
      ActionListener connectListener = new ConnectListener();
      connectButton.addActionListener( connectListener );
      connectMenuItem.addActionListener( connectListener );
      // create ImageIcon for disconnect buttons
      Icon disconnectIcon = new ImageIcon(
         getClass().getResource( "images/Disconnect.gif" ) );
      // create disconnectButton and disconnectMenuItem
      disconnectButton = new JButton( "Disconnect", disconnectIcon );
      disconnectMenuItem = new JMenuItem( "Disconnect", disconnectIcon );     
      disconnectMenuItem.setMnemonic( 'D' );
      // disable disconnect buttons
      disconnectButton.setEnabled( false );
      disconnectMenuItem.setEnabled( false );
      // create DisconnectListener for disconnect buttons
      ActionListener disconnectListener = new DisconnectListener();
      disconnectButton.addActionListener( disconnectListener );
      disconnectMenuItem.addActionListener( disconnectListener );
      // add connect and disconnect JMenuItems to fileMenu
      serverMenu.add( connectMenuItem );
      serverMenu.add( disconnectMenuItem );
      serverMenu.add(showUsers);          
      // add connect and disconnect JButtons to buttonPanel
      JPanel buttonPanel = new JPanel();
      buttonPanel.add( connectButton );
      buttonPanel.add( disconnectButton );
      // create JTextArea for displaying messages and users
      messageArea = new JTextArea();
      users = new JTextArea();
      // disable editing and wrap words at end of line
      messageArea.setEditable( false );
      messageArea.setWrapStyleWord( true );
      messageArea.setLineWrap( true );
      // put messageArea and users in JScrollPane to enable scrolling
      JPanel messagePanel = new JPanel();
      messagePanel.setLayout( new BorderLayout( 10, 10 ) );
      messagePanel.add( new JScrollPane( messageArea ),
         BorderLayout.CENTER );
      messagePanel.add( new JScrollPane( users ),
         BorderLayout.WEST );
      // create JTextArea for entering new messages
      inputArea = new JTextArea( 4, 20 );
      inputArea.setWrapStyleWord( true );
      inputArea.setLineWrap( true );
      inputArea.setEditable( false );
      // create Icon for sendButton
      Icon sendIcon = new ImageIcon(
         getClass().getResource( "images/Send.gif" ) );
      // create sendButton and disable it
      sendButton = new JButton( "Send", sendIcon );
      sendButton.setEnabled( false );
      sendButton.addActionListener(
         new ActionListener() {
            // send new message when user activates sendButton
            public void actionPerformed( ActionEvent event )
               messageManager.sendMessage( userName,
                  inputArea.getText());
               // clear inputArea
               inputArea.setText("");
      // lay out inputArea and sendButton in BoxLayout and
      // add Box to messagePanel
      Box box = new Box( BoxLayout.X_AXIS );
      box.add( new JScrollPane( inputArea ) );
      box.add( sendButton );
      messagePanel.add( box, BorderLayout.SOUTH );
      // create JLabel for statusBar with a recessed border
      statusBar = new JLabel( "Not Connected" );
      statusBar.setBorder( new BevelBorder( BevelBorder.LOWERED ) );
      // lay out components in JFrame
      Container container = getContentPane();
      container.add( buttonPanel, BorderLayout.NORTH );
      container.add( messagePanel, BorderLayout.CENTER );
      container.add( statusBar, BorderLayout.SOUTH );
      // add WindowListener to disconnect when user quits
      addWindowListener (
         new WindowAdapter () {
            // disconnect from server and exit application
            public void windowClosing ( WindowEvent event )
               messageManager.disconnect( messageListener );
               System.exit( 0 );
   } // end ClientGUI constructor
   // ConnectListener listens for user requests to connect to server
   private class ConnectListener implements ActionListener {
      // connect to server and enable/disable GUI components
      public void actionPerformed( ActionEvent event )
         // connect to server and route messages to messageListener
         messageManager.connect( messageListener );
         // prompt for userName
         userName = JOptionPane.showInputDialog(
            ClientGUI.this, "Enter user name:" );
         dUserName = userName;
         dUserName = "Not Good";
                          String input = dUserName;
                    Connection foo = null;
                    PreparedStatement stmt = null;
                    try
                         foo = DriverManager.getConnection("jdbc:mysql://localhost/users?user=mike&password=blitz84");
                         stmt = foo.prepareStatement("INSERT INTO connections VALUES (?)");
                         stmt.setString(1, dUserName); // input is the name of the user as a String
                         stmt.executeUpdate();
                    catch (SQLException e)
                         foo.rollback();
                         e.printStackTrace();
                    finally
                         if (stmt != null) stmt.close();
                         if (foo != null) foo.close();
         // clear messageArea
         messageArea.setText( "" );
         // update GUI components
         connectButton.setEnabled( false );
         connectMenuItem.setEnabled( false );
         disconnectButton.setEnabled( true );
         disconnectMenuItem.setEnabled( true );
         sendButton.setEnabled( true );
         inputArea.setEditable( true );
         inputArea.requestFocus(); 
         statusBar.setText( "Connected: " + userName );
   } // end ConnectListener inner class
   // DisconnectListener listens for user requests to disconnect
   // from DeitelMessengerServer
   private class DisconnectListener implements ActionListener {
      // disconnect from server and enable/disable GUI components
      public void actionPerformed( ActionEvent event )
         // disconnect from server and stop routing messages
         // to messageListener
         messageManager.disconnect( messageListener );
         // update GUI components
         sendButton.setEnabled( false );
         disconnectButton.setEnabled( false );
         disconnectMenuItem.setEnabled( false );
         inputArea.setEditable( false );
         connectButton.setEnabled( true );        
         connectMenuItem.setEnabled( true );
         statusBar.setText( "Not Connected" );        
   } // end DisconnectListener inner class
   // MyMessageListener listens for new messages from MessageManager and
   // displays messages in messageArea using MessageDisplayer.
   private class MyMessageListener implements MessageListener {
      // when received, display new messages in messageArea
      public void messageReceived( String from, String message )
         // append message using MessageDisplayer and
         // invokeLater, ensuring thread-safe access messageArea
         SwingUtilities.invokeLater(
            new MessageDisplayer( from, message ) );
   // MessageDisplayer displays a new message by appending the message to
   // the messageArea JTextArea. This Runnable object should be executed
   // only on the Event thread, because it modifies a live Swing component
   private class MessageDisplayer implements Runnable {
      private String fromUser;
      private String messageBody;
      // MessageDisplayer constructor
      public MessageDisplayer( String from, String body )
         fromUser = from;
         messageBody = body;
      // display new message in messageArea
      public void run()
         // append new message
         messageArea.append( "\n" + fromUser + "> " + messageBody );  
         // move caret to end of messageArea to ensure new
         // message is visible on screen
         messageArea.setCaretPosition( messageArea.getText().length() );                         
   }// end MessageDisplayer inner class
} // end class ClientGUI
and here is the code that uses the above code:
package com.deitel.messenger.sockets.client;
import com.deitel.messenger.*;
public class DeitelMessenger {
   public static void main( String args[] )
      MessageManager messageManager;
      // create new DeitelMessenger
      if ( args.length == 0 )
         messageManager = new SocketMessageManager( "localhost" );
      else
         messageManager = new SocketMessageManager( args[ 0 ] ); 
      // create GUI for SocketMessageManager
      ClientGUI clientGUI = new ClientGUI( messageManager );
      clientGUI.setSize( 500, 400 );
      clientGUI.setResizable( false );
      clientGUI.setVisible( true );
} // end class DeitelMessenger