Java Graphics - 如何用QuadCurve2D.Float绘制四条曲线

import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.QuadCurve2D;

public class ShapeSampler extends Frame {
  public static void main(String[] args) {
    (new ShapeSampler()).setVisible(true);
  }

  public ShapeSampler() {
    super("Shape Sampler");
    setSize(400, 550);
  }

  public void paint(Graphics g) {
    Graphics2D g2d = (Graphics2D) g;

    QuadCurve2D quadcurve = new QuadCurve2D.Float(50, 300, 320, 300, 350, 400);
    g2d.draw(quadcurve);

  }
}