帮我重启一个swing按钮，要求为圆角，并且鼠标移动到按钮上面会改变按钮颜色

好的，为您提供一个简单的示例代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class RoundedButton extends JButton {
    public RoundedButton(String text) {
        super(text);
        setOpaque(false);
        setBorder(BorderFactory.createEmptyBorder(5, 15, 5, 15));
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseEntered(MouseEvent e) {
                setBackground(new Color(225, 225, 225));
            }

            @Override
            public void mouseExited(MouseEvent e) {
                setBackground(UIManager.getColor("control"));
            }
        });
    }

    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2 = (Graphics2D) g.create();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setColor(getBackground());
        g2.fillRoundRect(0, 0, getWidth(), getHeight(), 20, 20);
        g2.dispose();
        super.paintComponent(g);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(120, 40);
    }
}

您可以将此代码复制粘贴到一个新的类中，然后在您的代码中创建此类的实例并将其添加到您的swing界面中。