用java编写一个贪吃蛇

编写一个贪吃蛇游戏可以使用Java语言和Java Swing库，下面是一个简单的贪吃蛇游戏实现的示例代码：

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import java.util.Random;

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

public class SnakeGame extends JPanel implements ActionListener, KeyListener {
    private static final long serialVersionUID = 1L;

    public static final int WIDTH = 500;
    public static final int HEIGHT = 500;
    public static final int DOT_SIZE = 10;
    public static final int ALL_DOTS = (WIDTH * HEIGHT) / (DOT_SIZE * DOT_SIZE);
    public static final int RAND_POS = (WIDTH / DOT_SIZE) * (HEIGHT / DOT_SIZE);

    private ArrayList<Point> snake;
    private Point food;
    private Timer timer;
    private boolean inGame;
    private int score;

    private int[] x = new int[ALL_DOTS];
    private int[] y = new int[ALL_DOTS];

    private boolean leftDirection = false;
    private boolean rightDirection = true;
    private boolean upDirection = false;
    private boolean downDirection = false;

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

        initGame();
    }

    private void initGame() {
        snake = new ArrayList<Point>();
        score = 0;
        inGame = true;

        for (int i = 0; i < 3; i++) {
            x[i] = 50 - i * DOT_SIZE;
            y[i] = 50;
            snake.add(new Point(x[i], y[i]));
        }

        generateFood();

        timer = new Timer(100, this);
        timer.start();
    }

    private void generateFood() {
        Random rand = new Random();

        int r = rand.nextInt(RAND_POS);
        int foodX = ((r * DOT_SIZE));

        r = rand.nextInt(RAND_POS);
        int foodY = ((r * DOT_SIZE));

        food = new Point(foodX, foodY);
    }

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

        if (inGame) {
            g.setColor(Color.green);
            g.fillOval(food.x, food.y, DOT_SIZE, DOT_SIZE);

            for (int i = 0; i < snake.size(); i++) {
                g.setColor(Color.white);
                g.fillOval(snake.get(i).x, snake.get(i).y, DOT_SIZE, DOT_SIZE);
            }

            g.setColor(Color.white);
            g.drawString("Score: " + score, 10, 20);
        } else {
            g.setColor(Color.white);
            g.drawString("Game Over", WIDTH / 2 - 30, HEIGHT / 2);
        }
    }

    private void move() {
        for (int i = snake.size() - 1; i > 0; i--) {
            snake.set(i, snake.get(i - 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;
        }

        snake.set(0, new Point(x[0], y[0]));
    }

    private void checkCollision() {
        for (int i = snake.size() - 1; i > 0; i--) {
            if (snake.get(0).equals(snake.get(i))) {
                inGame = false;
            }
        }

        if (snake.get(0).x < 0 || snake.get(0).x > WIDTH - DOT_SIZE || snake.get(0).y < 0 || snake.get(0).y > HEIGHT - DOT_SIZE) {
            inGame = false;
        }

        if (inGame && snake.get(0).equals(food)) {
            score++;
            generateFood();
            snake.add(new Point(x[snake.size() - 1], y[snake.size() - 1]));
        }
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (inGame) {
            checkCollision();
            move();
        }

        repaint();
    }

    @Override
    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;
        }
    }

    @Override
    public void keyReleased(KeyEvent arg0) {
    }

    @Override
    public void keyTyped(KeyEvent arg0) {
    }

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

这个示例代码实现了一个简单的贪吃蛇游戏，其中使用了Java Swing库实现了游戏界面和游戏逻辑，通过键盘控制贪吃蛇的移动并实现吃食物得分的功能。你可以根据自己的需求进行修改和扩展。