java实现雪花飘落效果(附完整源码)

以下是Java实现雪花飘落效果的完整源码：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Snowfall extends JPanel implements Runnable {

    private static final int WIDTH = 800;
    private static final int HEIGHT = 600;
    private static final int NUM_OF_SNOWFLAKES = 100;
    private static final int DELAY = 25;

    private ArrayList<Snowflake> snowflakes;

    public Snowfall() {
        snowflakes = new ArrayList<>();
        Random rand = new Random();
        for (int i = 0; i < NUM_OF_SNOWFLAKES; i++) {
            int x = rand.nextInt(WIDTH);
            int y = rand.nextInt(HEIGHT);
            int speed = rand.nextInt(5) + 1;
            snowflakes.add(new Snowflake(x, y, speed));
        }
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.WHITE);
        for (Snowflake s : snowflakes) {
            g.fillOval(s.getX(), s.getY(), 5, 5);
        }
    }

    @Override
    public void run() {
        while (true) {
            for (Snowflake s : snowflakes) {
                s.move();
            }
            repaint();
            try {
                Thread.sleep(DELAY);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }
    }

    private class Snowflake {

        private int x;
        private int y;
        private int speed;

        public Snowflake(int x, int y, int speed) {
            this.x = x;
            this.y = y;
            this.speed = speed;
        }

        public int getX() {
            return x;
        }

        public int getY() {
            return y;
        }

        public void move() {
            Random rand = new Random();
            int newX = x - speed + rand.nextInt(3);
            int newY = y + speed + rand.nextInt(3);
            if (newX < 0 || newX > WIDTH || newY > HEIGHT) {
                newX = rand.nextInt(WIDTH);
                newY = rand.nextInt(HEIGHT / 4);
            }
            x = newX;
            y = newY;
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Snowfall");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(WIDTH, HEIGHT);
        Snowfall snowfall = new Snowfall();
        frame.add(snowfall);
        frame.setVisible(true);
        new Thread(snowfall).start();
    }
}

运行这个程序，你将会看到一个简单的窗口，其中有100个雪花飘落。在这个程序中，我们首先在构造函数中创建一些雪花对象，这些对象具有随机的位置和速度。然后，在重绘方法中，我们遍历所有的雪花对象，并绘制它们。在运行方法中，我们不断移动每个雪花对象，并重新绘制窗口。