changepassword.java

采用GUI格式调用的库函数直接写的源码

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.LineBorder;
import java.sql.*;
import java.util.*;
import java.util.EventListener.*;
import java.text.*;

public class ChangePassword extends JInternalFrame implements ActionListener {

	private JPanel pChange = new JPanel();
	private JLabel lbUser, lbPass, lbNew;
	public JTextField txtUser;
	public JPasswordField txtPass, txtNew;
	private JButton btnOk, btnCancel;

	private Statement st;			//Statement for Getting the Required Table.
	public String userName;			//For Holding the Usename.

	//Constructor of Class.	

	public ChangePassword (String user, Connection con) {

		//super(Title, Resizable, Closable, Maximizable, Iconifiable)
		super ("Change Password", false, true, false, true);
		setSize (300, 210);

		//Setting the Form's Labels.

		lbUser = new JLabel ("Username:");
		lbUser.setForeground (Color.black);
		lbUser.setBounds (20, 20, 115, 25);
	        lbPass = new JLabel ("Old Password:");
		lbPass.setForeground (Color.black);
        	lbPass.setBounds (20, 55, 115, 25);
	        lbNew = new JLabel ("New Password:");
		lbNew.setForeground (Color.black);
	        lbNew.setBounds (20, 90, 115, 25);

		//Setting the Form's TextField & PasswordField.

		txtUser = new JTextField ();
		txtUser.setEnabled (false);
		txtUser.setBounds (120, 20, 150, 25);
		txtUser.setText (user);
		txtPass = new JPasswordField ();
		txtPass.setBounds (120, 55, 150, 25);
		txtNew = new JPasswordField ();
		txtNew.setBounds (120, 90, 150, 25);

		//Setting the Form's Buttons.

		btnOk = new JButton ("OK");
		btnOk.setBounds (20, 130, 100, 25);
		btnOk.addActionListener (this);
		btnCancel = new JButton ("Cancel");
		btnCancel.setBounds (165, 130, 100, 25);
		btnCancel.addActionListener (this);

		//Setting Panel's Layout.

		pChange.setLayout (null);

		//Adding All the Controls in Panel.

		pChange.add (lbUser);
		pChange.add (lbPass);
		pChange.add (lbNew);
		pChange.add (txtUser);
		pChange.add (txtPass);
		pChange.add (txtNew);
		pChange.add (btnOk);
		pChange.add (btnCancel);

		//Adding Panel to the Form.

		getContentPane().add (pChange);

		userName = user;	//Getting Username.

		try {
			st = con.createStatement ();	//Creating Statement Object.
		}
		catch (SQLException sqlex) {			//If Problem then Show the User a Message.
 			JOptionPane.showMessageDialog (null, "A Problem Occurs While Loading the Form.");
 			dispose ();				//Closing the Form.
	 	}

		setVisible (true);

	}

	public void actionPerformed (ActionEvent ae) {

		Object obj = ae.getSource();

		if (obj == btnOk) {		//If OK Button Pressed.

			String oldPass = new String (txtPass.getPassword());
			String newPass = new String (txtNew.getPassword());

			if (oldPass.equals ("")) {
				JOptionPane.showMessageDialog (this, "Old Password not Provided.");
				txtPass.requestFocus ();
			}
			else if (newPass.equals ("")) {
				JOptionPane.showMessageDialog (this, "New Password not Provided.");
				txtNew.requestFocus ();
			}
			else {
				String pass;			//To Hold the Password.
				boolean verify = false;		//To Confirm Logon.

	 			try {	//SELECT Query to Retrieved the Record.
 					String query = "SELECT * FROM Users WHERE Username = '" + userName + "'";

		 			ResultSet rs = st.executeQuery (query);		//Executing the Query.
					rs.next();					//Moving Towards the Record.
 					pass = rs.getString ("Password");		//Storing Password.

 					if (oldPass.equals (pass)) {		//If Found then.
						verify = true;
						String q = "UPDATE Users SET Password = '" + newPass + 
							"' WHERE Username = '" + userName + "'";

						int result = st.executeUpdate (q);
						if (result == 1) {
							JOptionPane.showMessageDialog (this, 
							"Your Password has been Changed.\nRemember Your new Password");
							setVisible (false);		//Hide the Form.
							dispose();            		//Free the System Resources.
						}
						else {
							JOptionPane.showMessageDialog (this, "Problem in Changing Password.");
							txtPass.setText ("");
							txtNew.setText ("");
							txtPass.requestFocus ();
						}
					}
					else {
						verify = false;
						txtPass.setText ("");
						txtNew.setText ("");
						txtPass.requestFocus ();
						JOptionPane.showMessageDialog (this, "Incorrect Old Password.");
					}
				}
				catch (SQLException sqlex) { }
			}

		}
		else if (obj == btnCancel) {		//If Cancel Button Pressed Unload the From.

			setVisible (false);
			dispose();

		}

	}

}