设计一个贪吃蛇游戏利用java并且具有暂停功能

好的，下面是一个简单的贪吃蛇游戏的Java代码，同时也包含了暂停功能的实现：

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

public class SnakeGame extends JFrame implements ActionListener {
    private final int WIDTH = 500; // 游戏窗口宽度
    private final int HEIGHT = 500; // 游戏窗口高度
    private final int UNIT_SIZE = 10; // 蛇身体单位大小
    private final int MAX_UNITS = (WIDTH * HEIGHT) / UNIT_SIZE; // 蛇身体最大长度
    private final int DELAY = 100; // 游戏速度
    private int x[] = new int[MAX_UNITS]; // 蛇身体X坐标
    private int y[] = new int[MAX_UNITS]; // 蛇身体Y坐标
    private int bodyParts = 6; // 蛇身体长度
    private int appleX; // 苹果X坐标
    private int appleY; // 苹果Y坐标
    private char direction = 'R'; // 蛇移动方向
    private boolean running = false; // 游戏是否正在运行
    private Timer timer; // 游戏计时器
    private JButton pauseButton; // 暂停按钮

    public SnakeGame() {
        initGame();
        initUI();
    }

    private void initGame() { // 初始化游戏
        addKeyListener(new MyKeyAdapter());
        setPreferredSize(new Dimension(WIDTH, HEIGHT));
        setBackground(Color.BLACK);
        setFocusable(true);
        initSnake();
        newApple();
        running = true;
        timer = new Timer(DELAY, this);
        timer.start();
    }

    private void initUI() { // 初始化UI界面
        pauseButton = new JButton("暂停");
        pauseButton.addActionListener(this);
        JPanel buttonPanel = new JPanel();
        buttonPanel.add(pauseButton);
        add(buttonPanel, BorderLayout.SOUTH);
        pack();
        setLocationRelativeTo(null);
        setVisible(true);
    }

    private void initSnake() { // 初始化蛇
        bodyParts = 6;
        for (int i = 0; i < bodyParts; i++) {
            x[i] = (WIDTH / 2) - (i * UNIT_SIZE);
            y[i] = (HEIGHT / 2);
        }
    }

    private void newApple() { // 新增苹果
        appleX = (int) (Math.random() * (WIDTH / UNIT_SIZE)) * UNIT_SIZE;
        appleY = (int) (Math.random() * (HEIGHT / UNIT_SIZE)) * UNIT_SIZE;
    }

    private void move() { // 蛇的移动
        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;
        }
    }

    private void checkApple() { // 检查是否吃到苹果
        if ((x[0] == appleX) && (y[0] == appleY)) {
            bodyParts++;
            newApple();
        }
    }

    private void checkCollision() { // 检查碰撞
        for (int i = bodyParts; i > 0; i--) {
            if ((x[0] == x[i]) && (y[0] == y[i])) {
                running = false;
            }
        }
        if (x[0] < 0) {
            running = false;
        }
        if (x[0] > WIDTH) {
            running = false;
        }
        if (y[0] < 0) {
            running = false;
        }
        if (y[0] > HEIGHT) {
            running = false;
        }
        if (!running) {
            timer.stop();
        }
    }

    private void gameOver(Graphics g) { // 游戏结束
        String message = "游戏结束！";
        Font font = new Font("Times New Roman", Font.BOLD, 30);
        FontMetrics metrics = getFontMetrics(font);
        g.setColor(Color.WHITE);
        g.setFont(font);
        g.drawString(message, (WIDTH - metrics.stringWidth(message)) / 2, (HEIGHT / 2));
    }

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

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

    private void draw(Graphics g) { // 画出游戏界面
        if (running) {
            g.setColor(Color.RED);
            g.fillOval(appleX, appleY, UNIT_SIZE, UNIT_SIZE);
            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(Color.YELLOW);
                    g.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
                }
            }
        } else {
            gameOver(g);
        }
    }

    private class MyKeyAdapter extends KeyAdapter { // 键盘监听

        @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;
            }
        }
    }

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

上述代码中，实现了一个简单的贪吃蛇游戏，并且包含了暂停功能。具体实现方式为在界面下方添加一个“暂停”按钮，点击后暂停游戏计时器，游戏界面停止更新。