在处理中使用鼠标坐标绘制箭头(Java)

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

public class ArrowDrawer extends JPanel {
    private Point startPoint;
    private Point endPoint;

    public ArrowDrawer() {
        addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                startPoint = e.getPoint();
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                endPoint = e.getPoint();
                repaint();
            }
        });
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        if (startPoint != null && endPoint != null) {
            Graphics2D g2d = (Graphics2D) g;
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.drawLine(startPoint.x, startPoint.y, endPoint.x, endPoint.y);
            // 绘制箭头头部
            int x1 = endPoint.x;
            int y1 = endPoint.y;
            int x2 = x1 - 10;
            int y2 = y1 - 5;
            int x3 = x1 - 10;
            int y3 = y1 + 5;
            g2d.fillPolygon(new int[]{x1, x2, x3}, new int[]{y1, y2, y3}, 3);
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Arrow Drawer");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new ArrowDrawer());
        frame.setSize(800, 600);
        frame.setVisible(true);
    }
}