贪吃蛇java源代码

以下是一个简单的贪吃蛇 Java 源代码示例：

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.LinkedList;
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;

    private static final int WIDTH = 500;
    private static final int HEIGHT = 500;

    private static final int DOT_SIZE = 10;
    private static final int ALL_DOTS = 900;
    private static final int RAND_POS = 29;

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

    private int dots;
    private int apple_x;
    private int apple_y;

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

    private Timer timer;
    private final Random rand = new Random();

    public SnakeGame() {
        addKeyListener(this);
        setBackground(Color.black);
        setFocusable(true);

        setPreferredSize(new Dimension(WIDTH, HEIGHT));

        initGame();
    }

    private void initGame() {
        dots = 3;

        for (int i = 0; i < dots; i++) {
            x[i] = 50 - i * DOT_SIZE;
            y[i] = 50;
        }

        locateApple();

        timer = new Timer(140, this);
        timer.start();
    }

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

        doDrawing(g);
    }

    private void doDrawing(Graphics g) {

        if (inGame) {

            g.setColor(Color.red);
            g.fillOval(apple_x, apple_y, DOT_SIZE, DOT_SIZE);

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

        } else {
            gameOver(g);
        }
    }

    private void gameOver(Graphics g) {

        String msg = "Game Over";
        g.setColor(Color.white);
        g.drawString(msg, (WIDTH - g.getFontMetrics().stringWidth(msg)) / 2, HEIGHT / 2);
    }

    private void checkApple() {

        if ((x[0] == apple_x) && (y[0] == apple_y)) {

            dots++;
            locateApple();
        }
    }

    private void move() {

        for (int i = dots; i > 0; i--) {
            x[i] = x[(i - 1)];
            y[i] = y[(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;
        }
    }

    private void checkCollision() {

        for (int i = dots; i > 0; i--) {

            if ((i > 4) && (x[0] == x[i]) && (y[0] == y[i])) {
                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 = rand.nextInt(RAND_POS);
        apple_x = ((r * DOT_SIZE));

        r = rand.nextInt(RAND_POS);
        apple_y = ((r * DOT_SIZE));
    }

    @Override
    public void actionPerformed(ActionEvent e) {

        if (inGame) {
            checkApple();
            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 e) {
    }

    @Override
    public void keyTyped(KeyEvent e) {
    }

    public static void main(String[] args) {

        JFrame f = new JFrame("Snake");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        SnakeGame game = new SnakeGame();

        f.add(game);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

以上代码实现了一个基本的贪吃蛇游戏。