运用java写一个贪吃蛇小游戏

好的，我可以为您提供一个简单的 Java 贪吃蛇小游戏示例。

游戏规则：
1. 贪吃蛇初始长度为 3，每次移动一格；
2. 贪吃蛇不能碰到边界，也不能碰到自己；
3. 有食物出现在随机位置，贪吃蛇吃到食物后长度加一；
4. 游戏结束条件为贪吃蛇碰到边界或自己。

下面是示例代码：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.LinkedList;

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

public class SnakeGame extends JPanel implements KeyListener {
    private static final long serialVersionUID = 1L;
    private static final int WIDTH = 500;
    private static final int HEIGHT = 500;
    private static final int UNIT_SIZE = 10;
    private static final int GAME_UNITS = (WIDTH * HEIGHT) / (UNIT_SIZE * UNIT_SIZE);
    private static final int DELAY = 75;
    private static final int[] X_OFFSET = { -1, 0, 1, 0 };
    private static final int[] Y_OFFSET = { 0, -1, 0, 1 };
    private static final Color SNAKE_COLOR = Color.GREEN;
    private static final Color FOOD_COLOR = Color.RED;

    private JFrame frame;
    private LinkedList<Point> snake;
    private Point food;
    private int direction;
    private boolean running;

    public SnakeGame() {
        frame = new JFrame("Snake Game");
        frame.setSize(WIDTH, HEIGHT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(this);
        frame.setVisible(true);
        frame.addKeyListener(this);

        snake = new LinkedList<Point>();
        snake.add(new Point(WIDTH / 2, HEIGHT / 2));
        snake.add(new Point(WIDTH / 2, HEIGHT / 2 + UNIT_SIZE));
        snake.add(new Point(WIDTH / 2, HEIGHT / 2 + 2 * UNIT_SIZE));

        direction = 0;
        running = true;

        spawnFood();

        new Thread(new Runnable() {
            public void run() {
                while (running) {
                    try {
                        Thread.sleep(DELAY);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    tick();
                    repaint();
                }
            }
        }).start();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        // 绘制贪吃蛇
        g.setColor(SNAKE_COLOR);
        for (Point p : snake) {
            g.fillRect(p.x, p.y, UNIT_SIZE, UNIT_SIZE);
        }

        // 绘制食物
        g.setColor(FOOD_COLOR);
        g.fillRect(food.x, food.y, UNIT_SIZE, UNIT_SIZE);
    }

    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        if (keyCode == KeyEvent.VK_LEFT && direction != 2) {
            direction = 0;
        } else if (keyCode == KeyEvent.VK_UP && direction != 3) {
            direction = 1;
        } else if (keyCode == KeyEvent.VK_RIGHT && direction != 0) {
            direction = 2;
        } else if (keyCode == KeyEvent.VK_DOWN && direction != 1) {
            direction = 3;
        }
    }

    public void keyTyped(KeyEvent e) {
    }

    public void keyReleased(KeyEvent e) {
    }

    private void tick() {
        // 移动贪吃蛇
        Point head = snake.getFirst();
        Point newHead = new Point(head.x + X_OFFSET[direction] * UNIT_SIZE,
                head.y + Y_OFFSET[direction] * UNIT_SIZE);
        if (newHead.x < 0 || newHead.x >= WIDTH || newHead.y < 0 || newHead.y >= HEIGHT) {
            // 碰到边界，游戏结束
            running = false;
            return;
        }
        for (Point p : snake) {
            if (p.equals(newHead)) {
                // 碰到自己，游戏结束
                running = false;
                return;
            }
        }
        snake.addFirst(newHead);
        if (newHead.equals(food)) {
            // 吃到食物，长度加一，重新生成食物
            spawnFood();
        } else {
            snake.removeLast();
        }
    }

    private void spawnFood() {
        Point p = new Point((int) (Math.random() * WIDTH / UNIT_SIZE) * UNIT_SIZE,
                (int) (Math.random() * HEIGHT / UNIT_SIZE) * UNIT_SIZE);
        while (snake.contains(p)) {
            p = new Point((int) (Math.random() * WIDTH / UNIT_SIZE) * UNIT_SIZE,
                    (int) (Math.random() * HEIGHT / UNIT_SIZE) * UNIT_SIZE);
        }
        food = p;
    }

    public static void main(String[] args) {
        new SnakeGame();
    }
}

希望这个示例可以帮助您了解如何用 Java 编写简单的贪吃蛇小游戏。