Java JPasswordField用法

本文概述

• JPasswordField类声明
• Java JPasswordField示例
• 带有ActionListener的Java JPasswordField示例

JPasswordField类的对象是专用于输入密码的文本组件。它允许编辑一行文本。它继承了JTextField类。

JPasswordField类声明

我们来看一下javax.swing.JPasswordField类的声明。

public class JPasswordField extends JTextField

常用的构造函数：

Java JPasswordField示例

import javax.swing.*;  
public class PasswordFieldExample {
	public static void main(String[] args) {  
	JFrame f=new JFrame("Password Field Example");  
	 JPasswordField value = new JPasswordField(); 
	 JLabel l1=new JLabel("Password:");  
	    l1.setBounds(20, 100, 80, 30);  
	     value.setBounds(100, 100, 100, 30);  
            f.add(value);  f.add(l1);
            f.setSize(300, 300);  
            f.setLayout(null);  
            f.setVisible(true);   
}
}

输出：

带有ActionListener的Java JPasswordField示例

import javax.swing.*;  
import java.awt.event.*;
public class PasswordFieldExample {
	public static void main(String[] args) {  
	JFrame f=new JFrame("Password Field Example");  
	 final JLabel label = new JLabel();          
	 label.setBounds(20, 150, 200, 50);
	 final JPasswordField value = new JPasswordField(); 
	 value.setBounds(100, 75, 100, 30); 
	 JLabel l1=new JLabel("Username:");  
	    l1.setBounds(20, 20, 80, 30);  
	    JLabel l2=new JLabel("Password:");  
	    l2.setBounds(20, 75, 80, 30);  
	    JButton b = new JButton("Login");
	    b.setBounds(100, 120, 80, 30);  
	    final JTextField text = new JTextField();
	    text.setBounds(100, 20, 100, 30);  
                f.add(value); f.add(l1); f.add(label); f.add(l2); f.add(b); f.add(text);
                f.setSize(300, 300);  
                f.setLayout(null);  
                f.setVisible(true);   
                b.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {     
                   String data = "Username " + text.getText();
                   data += ", Password: " 
                   + new String(value.getPassword()); 
                   label.setText(data);        
                }
             }); 
}
}

输出：