用java语言写一个贪吃蛇游戏

好的，下面是一个简单的贪吃蛇游戏的示例代码：

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

public class SnakeGame extends JFrame implements ActionListener {
    private final int WIDTH = 500;
    private final int HEIGHT = 500;
    private final int DOT_SIZE = 10;
    private final int MAX_DOTS = (WIDTH * HEIGHT) / (DOT_SIZE * DOT_SIZE);
    private int apple_x, apple_y;
    private int dots;
    private int x[] = new int[MAX_DOTS];
    private int y[] = new int[MAX_DOTS];
    private boolean leftDirection = false;
    private boolean rightDirection = true;
    private boolean upDirection = false;
    private boolean downDirection = false;
    private boolean inGame = true;
    private Timer timer;
    private Image ball;
    private Image apple;
    private Image head;

    public SnakeGame() {
        initGame();
        initWindow();
    }

    private void initGame() {
        dots = 3;
        for (int z = 0; z < dots; z++) {
            x[z] = 50 - z * DOT_SIZE;
            y[z] = 50;
        }
        locateApple();
        timer = new Timer(140, this);
        timer.start();
    }

    private void initWindow() {
        setTitle("Snake");
        setSize(WIDTH, HEIGHT);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        addKeyListener(new TAdapter());
        ball = new ImageIcon("dot.png").getImage();
        apple = new ImageIcon("apple.png").getImage();
        head = new ImageIcon("head.png").getImage();
    }

    private void checkApple() {
        if ((x[0] == apple_x) && (y[0] == apple_y)) {
            dots++;
            locateApple();
        }
    }

    private void move() {
        for (int z = dots; z > 0; z--) {
            x[z] = x[(z - 1)];
            y[z] = y[(z - 1)];
        }
        if (leftDirection) {
            x[0] -= DOT_SIZE;
        }
        if (rightDirection) {
            x[0] += DOT_SIZE;
        }
        if (upDirection) {
            y[0] -= DOT_SIZE;
        }
        if (downDirection) {
            y[0] += DOT_SIZE;
        }
    }

    private void checkCollision() {
        for (int z = dots; z > 0; z--) {
            if ((z > 4) && (x[0] == x[z]) && (y[0] == y[z])) {
                inGame = false;
            }
        }
        if (y[0] >= HEIGHT) {
            inGame = false;
        }
        if (y[0] < 0) {
            inGame = false;
        }
        if (x[0] >= WIDTH) {
            inGame = false;
        }
        if (x[0] < 0) {
            inGame = false;
        }
        if (!inGame) {
            timer.stop();
        }
    }

    private void locateApple() {
        int r = (int) (Math.random() * (WIDTH - DOT_SIZE));
        apple_x = ((r / DOT_SIZE) * DOT_SIZE);
        r = (int) (Math.random() * (HEIGHT - DOT_SIZE));
        apple_y = ((r / DOT_SIZE) * DOT_SIZE);
    }

    private void draw(Graphics g) {
        if (inGame) {
            g.drawImage(apple, apple_x, apple_y, this);
            for (int z = 0; z < dots; z++) {
                if (z == 0) {
                    g.drawImage(head, x[z], y[z], this);
                } else {
                    g.drawImage(ball, x[z], y[z], this);
                }
            }
            Toolkit.getDefaultToolkit().sync();
        } else {
            gameOver(g);
        }
    }

    private void gameOver(Graphics g) {
        String msg = "Game Over";
        Font small = new Font("Helvetica", Font.BOLD, 14);
        FontMetrics metr = getFontMetrics(small);
        g.setColor(Color.white);
        g.setFont(small);
        g.drawString(msg, (WIDTH - metr.stringWidth(msg)) / 2, HEIGHT / 2);
    }

    public void actionPerformed(ActionEvent e) {
        if (inGame) {
            checkApple();
            checkCollision();
            move();
        }
        repaint();
    }

    private class TAdapter extends KeyAdapter {
        public void keyPressed(KeyEvent e) {
            int key = e.getKeyCode();
            if ((key == KeyEvent.VK_LEFT) && (!rightDirection)) {
                leftDirection = true;
                upDirection = false;
                downDirection = false;
            }
            if ((key == KeyEvent.VK_RIGHT) && (!leftDirection)) {
                rightDirection = true;
                upDirection = false;
                downDirection = false;
            }
            if ((key == KeyEvent.VK_UP) && (!downDirection)) {
                upDirection = true;
                rightDirection = false;
                leftDirection = false;
            }
            if ((key == KeyEvent.VK_DOWN) && (!upDirection)) {
                downDirection = true;
                rightDirection = false;
                leftDirection = false;
            }
        }
    }

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

在这个示例代码中，我们使用了 Java 的 Swing 库来实现图形化界面，通过键盘事件监听器来捕捉用户的操作，并在定时器的帮助下不断更新贪吃蛇的状态。你可以自己运行一下这个程序，看看效果如何。