jtextpassworddemo.java

精通Java核心技术源代码

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class JTextPasswordDemo extends JFrame 
{
		private String username,password;
		JTextField textField;
		JPasswordField passwordField;
	
		public JTextPasswordDemo()
		{	
			super( "JTextPasswordDemo" );
		
			// 获取content pane并设置布局管理器
			Container container = getContentPane();
			container.setLayout( new FlowLayout() );
	   
			// 创建text label和text field
			JLabel textLabel = new JLabel( "Username: " );
			textField = new JTextField( 10 );
	   
			// 创建password label和password field
			JLabel passwordLabel = new JLabel( "Password: " );
			passwordField = new JPasswordField( 10 );
			passwordField.setEchoChar( '*' );
       
			// 注册时间处理器
			EventHandler handler = new EventHandler();
			textField.addActionListener( handler );
			passwordField.addActionListener( handler );
	
			container.add( textLabel );
			container.add( textField );
			container.add( passwordLabel );
			container.add( passwordField );
	   
			setSize( 260,110 );
			setVisible( true );
		}
	
		// 用于事件处理的内部类
		private class EventHandler implements ActionListener
		{
			public void actionPerformed( ActionEvent event )
			{
				String output = "";
			
				// 在textField处按回车键
				if ( event.getSource() == textField )
			  	output = "Username:" + event.getActionCommand();
			
				// 在passwordField处按回车键
				else if ( event.getSource() == passwordField )
			 	output = "Password:" + new String( passwordField.getPassword() );
			
				JOptionPane.showMessageDialog( null,output );
		   	}
		}
	
		public static void main( String args[] )
	    {
			JTextPasswordDemo jtp = new JTextPasswordDemo();
			jtp.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	    }
	}