java代码画樱花飘落_樱花的季节，教大家用canvas画出飞舞的樱花树

好的，下面是 Java 代码画出飞舞的樱花树：

import javax.swing.*;
import java.awt.*;
import java.util.Random;

public class SakuraTree extends JFrame {
    private final int WIDTH = 800;
    private final int HEIGHT = 600;
    private final int DELAY = 30;
    private final int FLOWER_NUM = 50;

    private Image buffer;
    private Graphics bufferGraphics;
    private Random random = new Random();
    private Flower[] flowers = new Flower[FLOWER_NUM];
    private int[] xPoints = {0, 20, 20, 40, 20, 20, 0};
    private int[] yPoints = {0, 20, 40, 20, 20, 0, 20};

    public SakuraTree() {
        setTitle("Sakura Tree");
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);

        buffer = createImage(WIDTH, HEIGHT);
        bufferGraphics = buffer.getGraphics();

        for (int i = 0; i < FLOWER_NUM; i++) {
            int x = random.nextInt(WIDTH);
            int y = random.nextInt(HEIGHT / 2);
            int dx = random.nextInt(5) + 1;
            int dy = random.nextInt(5) + 1;
            int size = random.nextInt(20) + 10;
            flowers[i] = new Flower(x, y, dx, dy, size);
        }

        Timer timer = new Timer(DELAY, e -> {
            bufferGraphics.setColor(Color.WHITE);
            bufferGraphics.fillRect(0, 0, WIDTH, HEIGHT);

            for (Flower flower : flowers) {
                flower.draw(bufferGraphics);
                flower.update();
            }

            repaint();
        });
        timer.start();
    }

    @Override
    public void paint(Graphics g) {
        g.drawImage(buffer, 0, 0, this);
    }

    private class Flower {
        private int x;
        private int y;
        private int dx;
        private int dy;
        private int size;

        public Flower(int x, int y, int dx, int dy, int size) {
            this.x = x;
            this.y = y;
            this.dx = dx;
            this.dy = dy;
            this.size = size;
        }

        public void draw(Graphics g) {
            g.setColor(Color.PINK);
            for (int i = 0; i < 7; i++) {
                int xPoint = x + xPoints[i] * size / 40;
                int yPoint = y + yPoints[i] * size / 40;
                g.fillOval(xPoint, yPoint, size / 4, size / 4);
            }
        }

        public void update() {
            x += dx;
            y += dy;

            if (x < 0 || x > WIDTH - size / 4) {
                dx = -dx;
            }

            if (y < 0 || y > HEIGHT / 2 - size / 4) {
                dy = -dy;
            }
        }
    }

    public static void main(String[] args) {
        new SakuraTree().setVisible(true);
    }
}

这个程序使用了 Java Swing 绘制界面，通过 Timer 类定时更新画面。其中，Flower 类代表樱花，包含了绘制和更新的方法。在主程序中创建了 50 朵樱花，并且使用随机数来设置它们的位置、速度和大小。每个樱花使用 7 个点来绘制，颜色为粉色，形状为圆形。它们会在界面中飘动，并且会在到达屏幕边缘时反弹。