你可以用java写一个贪吃蛇小游戏吗

当然可以！以下是一个简单的Java贪吃蛇小游戏的实现代码，供你参考：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
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;

public class SnakeGame extends JPanel implements KeyListener {
    private static final long serialVersionUID = 1L;
    private static final int BOX_WIDTH = 20;
    private static final int BOX_HEIGHT = 20;
    private static final int BOARD_WIDTH = 20;
    private static final int BOARD_HEIGHT = 20;
    private static final int INITIAL_SNAKE_SIZE = 3;
    private static final int SLEEP_TIME = 100;
    private static final Random random = new Random();
    private ArrayList<Point> snake = new ArrayList<Point>();
    private Point food;
    private int direction = KeyEvent.VK_RIGHT;

    public SnakeGame() {
        setPreferredSize(new java.awt.Dimension(BOARD_WIDTH * BOX_WIDTH, BOARD_HEIGHT * BOX_HEIGHT));
        setBackground(Color.BLACK);
        setFocusable(true);
        addKeyListener(this);
        initGame();
    }

    private void initGame() {
        snake.clear();
        for (int i = 0; i < INITIAL_SNAKE_SIZE; i++) {
            snake.add(new Point(i, 0));
        }
        placeFood();
    }

    private void placeFood() {
        int x = random.nextInt(BOARD_WIDTH);
        int y = random.nextInt(BOARD_HEIGHT);
        food = new Point(x, y);
    }

    private void move() {
        Point head = snake.get(0);
        switch (direction) {
        case KeyEvent.VK_LEFT:
            head = new Point(head.x - 1, head.y);
            break;
        case KeyEvent.VK_RIGHT:
            head = new Point(head.x + 1, head.y);
            break;
        case KeyEvent.VK_UP:
            head = new Point(head.x, head.y - 1);
            break;
        case KeyEvent.VK_DOWN:
            head = new Point(head.x, head.y + 1);
            break;
        }
        snake.add(0, head);
        if (head.equals(food)) {
            placeFood();
        } else {
            snake.remove(snake.size() - 1);
        }
    }

    private boolean checkCollision() {
        Point head = snake.get(0);
        if (head.x < 0 || head.x >= BOARD_WIDTH || head.y < 0 || head.y >= BOARD_HEIGHT) {
            return true;
        }
        for (int i = 1; i < snake.size(); i++) {
            if (snake.get(i).equals(head)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int key = e.getKeyCode();
        if ((key == KeyEvent.VK_LEFT || key == KeyEvent.VK_RIGHT || key == KeyEvent.VK_UP || key == KeyEvent.VK_DOWN)
                && Math.abs(key - direction) != 2) {
            direction = key;
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {
    }

    @Override
    public void keyTyped(KeyEvent e) {
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(Color.RED);
        g.fillRect(food.x * BOX_WIDTH, food.y * BOX_HEIGHT, BOX_WIDTH, BOX_HEIGHT);
        g.setColor(Color.WHITE);
        for (Point p : snake) {
            g.fillRect(p.x * BOX_WIDTH, p.y * BOX_HEIGHT, BOX_WIDTH, BOX_HEIGHT);
        }
    }

    public void run() {
        while (true) {
            try {
                Thread.sleep(SLEEP_TIME);
            } catch (InterruptedException e) {
            }
            move();
            if (checkCollision()) {
                break;
            }
            repaint();
        }
    }

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

该代码使用了Java Swing绘制图形界面，并使用键盘事件处理玩家输入。游戏中使用ArrayList存储蛇的身体，使用Point表示每个蛇身体的坐标。在游戏中，我们先绘制一个食物，然后循环进行以下步骤：

1. 检查玩家是否碰撞到墙壁或自己的身体，如果是，则结束游戏。
2. 根据玩家输入更新蛇的方向，然后移动蛇的身体。
3. 如果蛇头碰到食物，重新生成一个食物。
4. 重新绘制游戏界面。

在游戏中，我们可以使用Java的线程来控制游戏的运行，使得游戏能够不断地更新，同时也不会阻塞主线程。