用 Java 写一个贪吃蛇小游戏

好的,我可以为您提供一个用Java编写的简单贪吃蛇小游戏的示例代码。这个游戏包含基本的贪吃蛇移动、吃食物和碰撞检测功能。以下是完整的代码:

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

public class SnakeGame extends JFrame {

    public SnakeGame() {
        this.add(new GamePanel());
        this.setTitle("贪吃蛇游戏");
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setResizable(false);
        this.pack();
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }

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

class GamePanel extends JPanel implements ActionListener {

    static final int SCREEN_WIDTH = 600;
    static final int SCREEN_HEIGHT = 600;
    static final int UNIT_SIZE = 25;
    static final int GAME_UNITS = (SCREEN_WIDTH*SCREEN_HEIGHT)/UNIT_SIZE;
    static final int DELAY = 75;
    final int[] x = new int[GAME_UNITS];
    final int[] y = new int[GAME_UNITS];
    int bodyParts = 6;
    int applesEaten;
    int appleX;
    int appleY;
    char direction = 'R';
    boolean running = false;
    Timer timer;
    Random random;

    public GamePanel() {
        random = new Random();
        this.setPreferredSize(new Dimension(SCREEN_WIDTH, SCREEN_HEIGHT));
        this.setBackground(Color.black);
        this.setFocusable(true);
        this.addKeyListener(new MyKeyAdapter());
        startGame();
    }

    public void startGame() {
        newApple();
        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) {
            // 画网格线
            /*
            for (int i = 0; i < SCREEN_HEIGHT/UNIT_SIZE; i++) {
                g.drawLine(i*UNIT_SIZE, 0, i*UNIT_SIZE, SCREEN_HEIGHT);
                g.drawLine(0, i*UNIT_SIZE, SCREEN_WIDTH, i*UNIT_SIZE);
            }
            */
            // 画食物
            g.setColor(Color.red);
            g.fillOval(appleX, appleY, UNIT_SIZE, UNIT_SIZE);

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

            // 画分数
            g.setColor(Color.red);
            g.setFont(new Font("Ink Free", Font.BOLD, 40));
            FontMetrics metrics = getFontMetrics(g.getFont());
            g.drawString("Score: " + applesEaten, (SCREEN_WIDTH - metrics.stringWidth("Score: " + applesEaten))/2, g.getFont().getSize());
        } else {
            gameOver(g);
        }
    }

    public void newApple() {
        appleX = random.nextInt((int)(SCREEN_WIDTH/UNIT_SIZE))*UNIT_SIZE;
        appleY = random.nextInt((int)(SCREEN_HEIGHT/UNIT_SIZE))*UNIT_SIZE;
    }

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

        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 checkApple() {
        if ((x[0] == appleX) && (y[0] == appleY)) {
            bodyParts++;
            applesEaten++;
            newApple();
        }
    }

    public void checkCollisions() {
        // 检查是否撞到自己
        for (int i = bodyParts; i > 0; i--) {
            if ((x[0] == x[i]) && (y[0] == y[i])) {
                running = false;
                break;
            }
        }

        // 检查是否撞到边界
        if (x[0] < 0 || x[0] >= SCREEN_WIDTH || y[0] < 0 || y[0] >= SCREEN_HEIGHT) {
            running = false;
        }

        if (!running) {
            timer.stop();
        }
    }

    public void gameOver(Graphics g) {
        // 画分数
        g.setColor(Color.red);
        g.setFont(new Font("Ink Free", Font.BOLD, 40));
        FontMetrics metrics1 = getFontMetrics(g.getFont());
        g.drawString("Score: " + applesEaten, (SCREEN_WIDTH - metrics1.stringWidth("Score: " + applesEaten))/2, g.getFont().getSize());

        // 画"游戏结束"
        g.setColor(Color.red);
        g.setFont(new Font("Ink Free", Font.BOLD, 75));
        FontMetrics metrics2 = getFontMetrics(g.getFont());
        g.drawString("Game Over", (SCREEN_WIDTH - metrics2.stringWidth("Game Over"))/2, SCREEN_HEIGHT/2);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (running) {
            move();
            checkApple();
            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;
            }
        }
    }
}

这个代码实现了以下功能：

1. 游戏窗口的创建和设置
2. 贪吃蛇的绘制和移动
3. 食物的生成和绘制
4. 碰撞检测（与自身和边界）
5. 分数统计和显示
6. 游戏结束画面

要运行这个游戏，你需要创建一个Java项目，将这段代码保存为`SnakeGame.java`，然后编译并运行它。游戏窗口会弹出，你可以使用箭头键来控制贪吃蛇的移动。