Java画图3

public class PaintUtil3 extends JPanel{
	/**
	 * 	动态图片
	 */
	private static final long serialVersionUID = -5247450804494766145L;
	private static BufferedImage image;
	int y = 0;
	int y1 = -600;
	
	static {
		image = loadImage("background.png");
	}
	
	/** 读取图片 */
	public static BufferedImage loadImage(String fileName) {
		try {
			//同包下读取图片
			BufferedImage img = ImageIO.read(PaintUtil3.class.getResource(fileName)); 
			return img;
		}catch(Exception e) {
			e.printStackTrace();
			throw new RuntimeException();
		}
	}
	
	private void backgroundLogic() {
		y += 5;
		y1 += 5;
		if(y >= 600) {
			y = -600;
		}
		if(y1 >= 600) {
			y1 = -600;
		}
	}
	
	/** 启动程序的执行 */
	public void action() {
		
		Timer timer = new Timer(); //定时器对象
		int interval = 10; //以毫秒为单位
		timer.schedule(new TimerTask() {
			public void run() { //定时干的那个事(每10毫秒走一次)
				backgroundLogic();
				
				repaint();     //重画(重新调用paint())
			}
		},interval,interval); //定时计划
	}
	
	/** 重写paint()画 g:画笔 */
	public void paint(Graphics g) {
		g.drawImage(image, 0, y, null);//在坐标（0，0）处画图，先画图再写字，不然会覆盖
		g.drawImage(image, 0, y1, null);//在坐标（0，0）处画图，先画图再写字，不然会覆盖
		
		g.setColor(Color.red);//设置颜色
		g.drawString("abcde", 111, 111 );//打字
		g.drawString("ABCDE", 300, 330);
		
	}	

	public static void main(String[] args) {
		JFrame frame = new JFrame("打飞机");
		PaintUtil3 pu = new PaintUtil3();//要求PaintUtil3是继承 JPanel父类
		
		frame.add(pu);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(400, 600);
		frame.setLocationRelativeTo(null); //中间
		frame.setVisible(true); //1)设计窗口可见  2)尽快调用paint()
		
		pu.action();//执行才会动态
	}
}

结果：背景向下移动