如何制作简单平面风格的JButton？

import javax.swing.*;
import java.awt.*;

public class SimpleFlatButtonDemo {
    public static void main(String[] args) {
        JFrame frame = new JFrame("简单平面风格的JButton");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(300, 200);

        JPanel panel = new JPanel();
        panel.setLayout(new FlowLayout());

        JButton flatButton = new JButton("点击我");
        flatButton.setFocusPainted(false);
        flatButton.setContentAreaFilled(true);
        flatButton.setBorderPainted(false);
        flatButton.setPreferredSize(new Dimension(150, 50));

        flatButton.addActionListener(e -> JOptionPane.showMessageDialog(frame, "您点击了平面风格的JButton！"));

        panel.add(flatButton);

        frame.add(panel);
        frame.setVisible(true);
    }
}