如何使用replaceAll函数来掩码数字？(Java GUI)

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

public class ReplaceAllGUI extends JFrame {
    private JTextField inputField;
    private JTextField outputField;
    private JButton maskButton;

    public ReplaceAllGUI() {
        setTitle("数字掩码示例");
        setSize(300, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 创建GUI组件
        inputField = new JTextField(20);
        outputField = new JTextField(20);
        outputField.setEditable(false);
        maskButton = new JButton("掩码");

        // 设置布局
        setLayout(new FlowLayout());

        // 添加组件到界面
        add(new JLabel("输入字符串："));
        add(inputField);
        add(new JLabel("掩码后的字符串："));
        add(outputField);
        add(maskButton);

        // 注册按钮点击事件监听器
        maskButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // 获取用户输入的字符串
                String input = inputField.getText();

                // 使用正则表达式替换数字部分为*
                String maskedString = input.replaceAll("\\d", "*");

                // 显示替换后的字符串
                outputField.setText(maskedString);
            }
        });
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                ReplaceAllGUI gui = new ReplaceAllGUI();
                gui.setVisible(true);
            }
        });
    }
}