文本框JTextField，密码框JPasswordField

1、文本框JTextField

public class Demo extends JFrame {
    public Demo() {
        setBounds(100, 100, 200, 120);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        Container c = getContentPane();
        c.setLayout(new FlowLayout());
        JTextField tf = new JTextField();//创建文本框
        tf.setColumns(15);//文本框长度
        tf.setText("黑体，加粗，20");
        tf.setFont(new Font("黑体", Font.BOLD, 20));
        c.add(tf);
        JButton btn = new JButton("打印");
        btn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.out.println(tf.getText());
                tf.setText("");//清空文本
                tf.requestFocus();//获取焦点
            }
        });
        c.add(btn);
        setVisible(true);
    }

    public static void main(String[] args) {
        new Demo();
    }
}

2、密码框JPasswordField

public class Demo extends JFrame {
    public Demo() {
        setBounds(100, 100, 200, 100);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        Container c = getContentPane();
        c.setLayout(new FlowLayout());
        JPasswordField pf = new JPasswordField();//密码框
        pf.setColumns(15);
        pf.addActionListener(new ActionListener() {//添加动作监听，回车触发
            public void actionPerformed(ActionEvent e) {
                System.out.println(pf.getPassword());
            }
        });
        c.add(pf);
        setVisible(true);
    }

    public static void main(String[] args) {
        new Demo();
    }
}