如何在jtextfield中顯示掩碼？

Question

我想在文本字段中顯示一個掩碼。我怎樣才能做到這一點？有沒有可重用的Java庫來做到這一點？我想創建一個僅允許輸入八位數的文本字段（每個數字應該爲0或1）

例如，

Answer 1

這將創建一個蒙面文本字段。當你按下輸入鍵時，它將輸出用戶輸入的內容。這使用JPasswordField。 http://docs.oracle.com/javase/1.4.2/docs/api/javax/swing/JPasswordField.html

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

public class PasswordField1 extends JApplet implements ActionListener { 
    /* Declaration */ 
    private JPasswordField Input; 
    private JTextField Echo; 
    private Container Panel; 
    private LayoutManager Layout; 

    public PasswordField1() { 
    /* Instantiation */ 
    Input = new JPasswordField ("", 20); 
    Layout = new FlowLayout(); 
    Panel = getContentPane(); 

    /* Location */ 
    Panel.setLayout (Layout); 
    Panel.add (Input); 

    /* Configuration */ 
    Input.addActionListener (this); 
    } 

    public void actionPerformed (ActionEvent e) { 
    char [] Chars; 
    String Word; 
    Chars = Input.getPassword(); 
    Word = new String(Chars); 
    System.out.println("You Entered: " + Word); 
    } 
}