我的矩形代码：

class Rectangle extends JPanel {

 int x = 105;
 int y= 100;
 int width = 50;
 int height = 100;


  public void paint(Graphics g) {
    g.drawRect (x, y, width, height);  
    g.setColor(Color.WHITE);
  }


Rectangle r = new Rectangle();

而我有一个按钮“旋转”。当用户用鼠标按下按钮时，矩形必须旋转15度。

这是我的操作代码：

public void actionPerformed(ActionEvent e){
    Object source  = e.getSource();

    if( source == rotate){
        AffineTransform transform = new AffineTransform();
        transform.rotate(Math.toRadians(15), r.getX() + r.getWidth()/2, r.getY() + height/2);
        r.add(transform);
    }
}

但是代码不起作用。我不知道为什么？你怎么想呢？

我编辑的操作代码部分：

public void actionPerformed(ActionEvent e){
        Object source  = e.getSource();

        if( source == rotate){

            Paint p = new Paint();              
            panel1.add(r);
             repaint();
        }
        }

    class Paint extends JPanel {
    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g;

        g2d.setColor(Color.WHITE);
        g2d.translate(r.getX()+(r.WIDTH/2), r.getY()+(r.HEIGHT/2));
        g2d.rotate(Math.toRadians(15));
        r.equals(g2d);
        repaint();
    }
}