//PasswordFieldTest.java

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

public class PasswordFieldTest
{  
	public static void main(String[] args)
	{  
		PasswordFieldFrame frame = new PasswordFieldFrame();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.show();
	}
}

class PasswordFieldFrame extends JFrame
{
	public PasswordFieldFrame()
	{
		setTitle("PasswordFieldTest");
		setSize(WIDTH, HEIGHT);

		Container contentPane = getContentPane();

		//新建文檔監聽器
		DocumentListener showListener = new ShowListener();

		//建立容納密碼域的面板
		JPanel textPanel = new JPanel();

		myPassword = new JPasswordField(20);
		//為密碼域安裝一個文檔監聽器
		myPassword.getDocument().addDocumentListener(showListener);
		textPanel.add(myPassword);

		checkPassword = new JTextField(20);
		checkPassword.setEditable(false);
		textPanel.add(checkPassword);

		contentPane.add(textPanel);
	}

	//獲取密碼域的內容，顯示在文本域中
	public void showPassword()
	{
		char[] s;
		String gets;

		//獲取密碼域的內容
		s = myPassword.getPassword();
		gets = new String(s);
		checkPassword.setText(gets);
	}

	private class ShowListener
		implements DocumentListener
	{
		public void insertUpdate(DocumentEvent e)
		{
			showPassword();
		}
		public void removeUpdate(DocumentEvent e)
		{
			showPassword();
		}
		public void changedUpdate(DocumentEvent e)
		{
		}
	}

	public static final int WIDTH = 350;
	public static final int HEIGHT = 150;

	private JPasswordField myPassword;
	private JTextField checkPassword;
}