如何从另一个java文件中使用对话框？

// DialogExample.java

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class DialogExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Main Frame");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        JButton button = new JButton("Open Dialog");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                showDialog();
            }
        });
        
        frame.getContentPane().add(button);
        frame.pack();
        frame.setVisible(true);
    }
    
    public static void showDialog() {
        JDialog dialog = new JDialog();
        dialog.setTitle("Dialog Example");
        dialog.setSize(200, 200);
        dialog.setLocationRelativeTo(null);
        dialog.setVisible(true);
    }
}