用java写贪吃蛇游戏，用上下左右键盘控制，吃完蛇身变长

A：

以下是Java实现贪吃蛇游戏的步骤：

1.创建一个Snake类，表示贪吃蛇。该类中包括：

a.表示蛇身体的数组；
b.蛇头的位置；
c.蛇身的长度；
d.蛇的成长速度；
e.蛇的方向；
f.蛇是否死亡。

2.创建一个Food类，表示食物。该类中包括：

a.表示食物的位置。

3.在窗口中绘制贪吃蛇和食物。

4.实现键盘控制。通过键盘可以改变蛇的方向。

5.监听贪吃蛇与食物的碰撞。如果碰撞了，则加分并增加蛇身长度。

以下是一个简单的Java代码实现：

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

public class SnakeGame extends JFrame implements KeyListener {

    private Snake snake;
    private Food food;
    private int score;
    private JLabel scoreLabel;

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

    SnakeGame() {
        setTitle("贪吃蛇");
        setSize(400, 400);
        setResizable(false);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        panel.setPreferredSize(new Dimension(400, 400));
        panel.setBackground(Color.white);
        add(panel);

        scoreLabel = new JLabel("得分：" + score);
        panel.add(scoreLabel);

        snake = new Snake();
        food = new Food();
        draw();

        setVisible(true);

        addKeyListener(this);
    }

    private void draw() {
        Graphics g = getGraphics();
        g.setColor(Color.white);
        g.fillRect(0, 0, 400, 400);

        food.draw(g);
        snake.draw(g);

        g.dispose();
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();
        switch (keyCode) {
            case KeyEvent.VK_UP:
                snake.changeDirection(SnakeDirection.UP);
                break;
            case KeyEvent.VK_DOWN:
                snake.changeDirection(SnakeDirection.DOWN);
                break;
            case KeyEvent.VK_LEFT:
                snake.changeDirection(SnakeDirection.LEFT);
                break;
            case KeyEvent.VK_RIGHT:
                snake.changeDirection(SnakeDirection.RIGHT);
                break;
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyTyped(KeyEvent e) {

    }

    private class Snake {

        private int length;
        private int growSpeed;
        private SnakeDirection direction;
        private int[][] body;
        private boolean dead;

        Snake() {
            length = 1;
            growSpeed = 2;
            direction = SnakeDirection.RIGHT;
            body = new int[100][2];
            body[0][0] = 10;
            body[0][1] = 10;
            dead = false;
        }

        void draw(Graphics g) {
            g.setColor(Color.green);
            for (int i = 0; i < length; i++) {
                g.fillRect(body[i][0], body[i][1], 10, 10);
            }
        }

        void changeDirection(SnakeDirection newDirection) {
            if (direction == SnakeDirection.UP && newDirection != SnakeDirection.DOWN) {
                direction = newDirection;
            } else if (direction == SnakeDirection.DOWN && newDirection != SnakeDirection.UP) {
                direction = newDirection;
            } else if (direction == SnakeDirection.LEFT && newDirection != SnakeDirection.RIGHT) {
                direction = newDirection;
            } else if (direction == SnakeDirection.RIGHT && newDirection != SnakeDirection.LEFT) {
                direction = newDirection;
            }
        }

        void move() {
            if (dead) {
                return;
            }
            for (int i = length - 1; i > 0; i--) {
                body[i][0] = body[i - 1][0];
                body[i][1] = body[i - 1][1];
            }
            switch (direction) {
                case UP:
                    body[0][1] -= 10;
                    break;
                case DOWN:
                    body[0][1] += 10;
                    break;
                case LEFT:
                    body[0][0] -= 10;
                    break;
                case RIGHT:
                    body[0][0] += 10;
                    break;
            }
            if (body[0][0] < 0 || body[0][0] >= 400 || body[0][1] < 0 || body[0][1] >= 400) {
                dead = true;
            }
            for (int i = 1; i < length; i++) {
                if (body[0][0] == body[i][0] && body[0][1] == body[i][1]) {
                    dead = true;
                    break;
                }
            }
            if (body[0][0] == food.x && body[0][1] == food.y) {
                score += growSpeed;
                scoreLabel.setText("得分：" + score);
                length += growSpeed;
                Random random = new Random();
                food.x = random.nextInt(39) * 10;
                food.y = random.nextInt(39) * 10;
            }
        }
    }

    private class Food {

        int x;
        int y;

        Food() {
            Random random = new Random();
            x = random.nextInt(39) * 10;
            y = random.nextInt(39) * 10;
        }

        void draw(Graphics g) {
            g.setColor(Color.red);
            g.fillOval(x, y, 10, 10);
        }
    }

    private enum SnakeDirection {
        UP,
        DOWN,
        LEFT,
        RIGHT
    }
}

以上是用Java语言实现贪吃蛇游戏的基本步骤，你可以和小伙伴一起挑战自己的最高分数。