如何在我的Java应用程序中将Enter指定为所有JButton的触发键？

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

public class Main {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Enter Key Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);

        JPanel panel = new JPanel();
        frame.add(panel);

        JButton button1 = new JButton("Button 1");
        JButton button2 = new JButton("Button 2");

        panel.add(button1);
        panel.add(button2);

        button1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (e.getSource() instanceof JButton) {
                    System.out.println("Button 1 clicked");
                }
            }
        });

        button2.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (e.getSource() instanceof JButton) {
                    System.out.println("Button 2 clicked");
                }
            }
        });

        frame.getRootPane().setDefaultButton(button1);
        frame.pack();
        frame.setVisible(true);
    }
}