JAVA飄雪，星星移動

 
 
 
 
 
 
 
 

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.util.Random;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class SnonDemo {

	public static void main(String[] args) {
		JFrame jFrame = new JFrame();
		jFrame.setTitle("飄雪");
		jFrame.setSize(800,600);
		jFrame.setResizable(false);
		jFrame.setLocationRelativeTo(null);
		jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		SnowPanel panel = new SnowPanel();
		//啓動線程
		Thread t = new Thread(panel);
		t.start();
		
		jFrame.add(panel);
		
		jFrame.setVisible(true);
	}

}

class SnowPanel extends JPanel implements Runnable{
	
	int[] snowX;//x座標集合
	int[] snowY;//y座標集合
	
	public SnowPanel(){
		//創建300個星星
		snowX = new int[300];
		snowY = new int[300];
		Random r = new Random();
		for(int i=0;i<snowX.length;i++){
			snowX[i] = r.nextInt(800);
			snowY[i] = r.nextInt(600);
		}
	}
	
	@Override
	public void paint(Graphics g){
		super.paint(g);
		setBackground(Color.BLACK);
		g.setColor(Color.WHITE);
		g.setFont(new Font("宋體",Font.PLAIN,15));
		for(int i=0;i<snowX.length;i++){
			g.drawString("*", snowX[i], snowY[i]);
		}
	}
	
	@Override
	public void run(){
		Random r = new Random();
		while(true){
			//1.修改星星座標
			for(int i=0;i<snowY.length;i++){
				//方式一
				if(snowY[i]>600){
//					snowY[i] = -snowY[i];
					snowY[i] = 0;
				}else{
					snowY[i]++;
				}
				//方式二
//				snowY[i]=(snowY[i]++)%600;
				//snowX[i] = r.nextInt(4)>1 ? snowX[i]-1 : snowX[i]+1 ;
			}
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			//2.重新繪畫
			repaint();
		}
	}
	
	
	
	
	
	
	
	
}