将饼图转换为JPanel netbeans

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class PieChartPanel extends JPanel {
    
    private int[] data; // 饼图数据
    
    public PieChartPanel(int[] data) {
        this.data = data;
        setPreferredSize(new Dimension(400, 400));
    }
    
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        
        int width = getWidth();
        int height = getHeight();
        int radius = Math.min(width, height) / 2;
        int centerX = width / 2;
        int centerY = height / 2;
        
        double total = 0;
        for (int value : data) {
            total += value;
        }
        
        double startAngle = 0;
        for (int i = 0; i < data.length; i++) {
            double arcAngle = data[i] / total * 360;
            g.setColor(getRandomColor());
            g.fillArc(centerX - radius, centerY - radius, radius * 2, radius * 2, (int) startAngle, (int) arcAngle);
            startAngle += arcAngle;
        }
    }
    
    private Color getRandomColor() {
        int r = (int) (Math.random() * 256);
        int g = (int) (Math.random() * 256);
        int b = (int) (Math.random() * 256);
        return new Color(r, g, b);
    }
    
    public static void main(String[] args) {
        int[] data = {30, 20, 10, 40}; // 示例数据
        
        JFrame frame = new JFrame("Pie Chart");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        PieChartPanel chartPanel = new PieChartPanel(data);
        frame.add(chartPanel);
        
        frame.pack();
        frame.setVisible(true);
    }
}