编写一个贪吃蛇的JAVA小游戏

好的，我来为您编写一个基本的贪吃蛇小游戏。游戏规则如下：

1. 贪吃蛇初始长度为3，每次吃到食物会增加1格长度。
2. 如果贪吃蛇撞到自己或者墙壁，游戏结束。
3. 食物每次随机生成在游戏区域内的一个位置。

以下是JAVA代码实现：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SnakeGame extends JPanel implements ActionListener {
    private final int WIDTH = 300;
    private final int HEIGHT = 300;
    private final int UNIT_SIZE = 10;
    private final int GAME_UNITS = (WIDTH * HEIGHT) / UNIT_SIZE;
    private final int DELAY = 100;
    private final int[] x = new int[GAME_UNITS];
    private final int[] y = new int[GAME_UNITS];
    private int bodyParts = 3;
    private int foodEaten;
    private int foodX;
    private int foodY;
    private char direction = 'R';
    private boolean running = false;
    private Timer timer;

    public SnakeGame() {
        setPreferredSize(new Dimension(WIDTH, HEIGHT));
        setBackground(Color.black);
        setFocusable(true);
        addKeyListener(new MyKeyAdapter());
        startGame();
    }

    public void startGame() {
        newFood();
        running = true;
        timer = new Timer(DELAY, this);
        timer.start();
    }

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

    public void draw(Graphics g) {
        if (running) {
            // 绘制食物
            g.setColor(Color.red);
            g.fillRect(foodX, foodY, UNIT_SIZE, UNIT_SIZE);

            // 绘制蛇身
            for (int i = 0; i < bodyParts; i++) {
                if (i == 0) {
                    g.setColor(Color.green);
                } else {
                    g.setColor(new Color(45, 180, 0));
                }
                g.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
            }

            // 绘制分数
            g.setColor(Color.white);
            g.drawString("得分：" + foodEaten, 10, 20);
        } else {
            gameOver(g);
        }
    }

    public void newFood() {
        foodX = (int) (Math.random() * (WIDTH / UNIT_SIZE)) * UNIT_SIZE;
        foodY = (int) (Math.random() * (HEIGHT / UNIT_SIZE)) * UNIT_SIZE;
    }

    public void move() {
        // 移动身体
        for (int i = bodyParts; i > 0; i--) {
            x[i] = x[i - 1];
            y[i] = y[i - 1];
        }

        // 移动头部
        switch (direction) {
            case 'U':
                y[0] = y[0] - UNIT_SIZE;
                break;
            case 'D':
                y[0] = y[0] + UNIT_SIZE;
                break;
            case 'L':
                x[0] = x[0] - UNIT_SIZE;
                break;
            case 'R':
                x[0] = x[0] + UNIT_SIZE;
                break;
        }
    }

    public void checkFood() {
        if (x[0] == foodX && y[0] == foodY) {
            bodyParts++;
            foodEaten++;
            newFood();
        }
    }

    public void checkCollisions() {
        // 撞墙检测
        for (int i = bodyParts; i > 0; i--) {
            if (x[0] == x[i] && y[0] == y[i]) {
                running = false;
            }
        }
        if (x[0] < 0 || x[0] >= WIDTH || y[0] < 0 || y[0] >= HEIGHT) {
            running = false;
        }
        if (!running) {
            timer.stop();
        }
    }

    public void gameOver(Graphics g) {
        g.setColor(Color.white);
        g.setFont(new Font("Ink Free", Font.BOLD, 40));
        FontMetrics metrics = getFontMetrics(g.getFont());
        g.drawString("Game Over", (WIDTH - metrics.stringWidth("Game Over")) / 2, HEIGHT / 2);
        g.drawString("得分：" + foodEaten, (WIDTH - metrics.stringWidth("得分：" + foodEaten)) / 2, (HEIGHT / 2) + 50);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (running) {
            move();
            checkFood();
            checkCollisions();
        }
        repaint();
    }

    public class MyKeyAdapter extends KeyAdapter {
        @Override
        public void keyPressed(KeyEvent e) {
            switch (e.getKeyCode()) {
                case KeyEvent.VK_LEFT:
                    if (direction != 'R') {
                        direction = 'L';
                    }
                    break;
                case KeyEvent.VK_RIGHT:
                    if (direction != 'L') {
                        direction = 'R';
                    }
                    break;
                case KeyEvent.VK_UP:
                    if (direction != 'D') {
                        direction = 'U';
                    }
                    break;
                case KeyEvent.VK_DOWN:
                    if (direction != 'U') {
                        direction = 'D';
                    }
                    break;
            }
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("贪吃蛇");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new SnakeGame());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

您可以将以上代码保存到一个名为`SnakeGame.java`的文件中，并使用JDK编译运行。