编写以下代码 用java swing做一款贪吃蛇游戏，要求有不同关卡

好的，下面是一个简单的Java Swing贪吃蛇游戏代码，其中包含有三个不同的关卡。这里提供的代码只是一个简单的示例，您可以根据自己的需要进行修改和扩展。

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

public class SnakeGame extends JFrame implements KeyListener {
    private static final long serialVersionUID = 1L;
    private final int ROWS = 20;
    private final int COLS = 20;
    private final int BLOCK_SIZE = 20;
    private final int MAX_LEVEL = 3;
    private int[][][] levels = {
        // level 1
        {
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
        },
        // level 2
        {
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 1, 1, 1, 1, 1, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 1, 0, 0, 0}
        },
        // level 3
        {
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
            {0, 0, 1, 1, 1, 1, 1, 1, 1, 0},
            {0, 0, 1, 0, 0, 0, 0, 0, 1, 0},
            {0, 0, 1, 0, 0, 0, 0, 0, 1, 0},
            {0, 0, 1, 0, 0, 0, 0, 0, 1, 0},
            {0, 0, 1, 0, 0, 0, 0, 0, 1, 0},
            {0, 0, 1, 1, 1, 1, 1, 1, 1, 0}
        }
    };
    private int[][] level = levels[0];
    private boolean[][] blocks = new boolean[ROWS][COLS];
    private int[] snakeX = new int[ROWS * COLS];
    private int[] snakeY = new int[ROWS * COLS];
    private int snakeLength = 0;
    private int foodX = 0;
    private int foodY = 0;
    private int direction = 0;
    private int levelIndex = 0;
    private int score = 0;

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

    public SnakeGame() {
        setTitle("Snake Game");
        setSize(COLS * BLOCK_SIZE + 20, ROWS * BLOCK_SIZE + 70);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        setLayout(null);

        JButton levelButton = new JButton("Level 1");
        levelButton.setBounds(10, 10, 80, 20);
        levelButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                levelIndex = 0;
                level = levels[levelIndex];
                resetGame();
            }
        });
        add(levelButton);

        JButton levelButton2 = new JButton("Level 2");
        levelButton2.setBounds(100, 10, 80, 20);
        levelButton2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                levelIndex = 1;
                level = levels[levelIndex];
                resetGame();
            }
        });
        add(levelButton2);

        JButton levelButton3 = new JButton("Level 3");
        levelButton3.setBounds(190, 10, 80, 20);
        levelButton3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                levelIndex = 2;
                level = levels[levelIndex];
                resetGame();
            }
        });
        add(levelButton3);

        setVisible(true);
        addKeyListener(this);
        setFocusable(true);

        resetGame();
        startGame();
    }

    private void resetGame() {
        for (int i = 0; i < ROWS; i++) {
            for (int j = 0; j < COLS; j++) {
                blocks[i][j] = (level[i][j] == 0);
            }
        }

        snakeX[0] = ROWS / 2;
        snakeY[0] = COLS / 2;
        snakeLength = 1;

        generateFood();
        direction = 0;
        score = 0;
    }

    private void generateFood() {
        while (true) {
            foodX = (int) (Math.random() * ROWS);
            foodY = (int) (Math.random() * COLS);
            if (blocks[foodX][foodY]) {
                break;
            }
        }
    }

    private void startGame() {
        Timer timer = new Timer(200 - levelIndex * 50, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                move();
                repaint();
            }
        });
        timer.start();
    }

    private void move() {
        int dx = (direction == 1) ? -1 : (direction == 3 ? 1 : 0);
        int dy = (direction == 0) ? -1 : (direction == 2 ? 1 : 0);
        int x = snakeX[0] + dx;
        int y = snakeY[0] + dy;
        if (x < 0 || x >= ROWS || y < 0 || y >= COLS || !blocks[x][y]) {
            JOptionPane.showMessageDialog(null, "Game Over!");
            resetGame();
            return;
        }
        for (int i = snakeLength - 1; i > 0; i--) {
            snakeX[i] = snakeX[i - 1];
            snakeY[i] = snakeY[i - 1];
        }
        snakeX[0] = x;
        snakeY[0] = y;
        if (x == foodX && y == foodY) {
            snakeLength++;
            score++;
            generateFood();
        }
    }

    public void paint(Graphics g) {
        super.paint(g);
        for (int i = 0; i < ROWS; i++) {
            for (int j = 0; j < COLS; j++) {
                if (blocks[i][j]) {
                    g.setColor(Color.GRAY);
                    g.fillRect(j * BLOCK_SIZE, i * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
                } else {
                    g.setColor(Color.WHITE);
                    g.fillRect(j * BLOCK_SIZE, i * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
                }
            }
        }
        for (int i = 0; i < snakeLength; i++) {
            g.setColor(Color.GREEN);
            g.fillRect(snakeY[i] * BLOCK_SIZE, snakeX[i] * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
        }
        g.setColor(Color.RED);
        g.fillOval(foodY * BLOCK_SIZE, foodX * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
        g.setColor(Color.BLACK);
        g.drawString("Score: " + score, 10, ROWS * BLOCK_SIZE + 20);
        g.drawString("Level: " + (levelIndex + 1), 100, ROWS * BLOCK_SIZE + 20);
    }

    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_UP && direction != 2) {
            direction = 0;
        } else if (code == KeyEvent.VK_DOWN && direction != 0) {
            direction = 2;
        } else if (code == KeyEvent.VK_LEFT && direction != 3) {
            direction = 1;
        } else if (code == KeyEvent.VK_RIGHT && direction != 1) {
            direction = 3;
        }
    }

    public void keyReleased(KeyEvent e) {
    }

    public void keyTyped(KeyEvent e) {
    }
}

这个代码实现了一个贪吃蛇游戏，包含有三个不同的关卡。在窗口中，有三个按钮，分别对应于不同的关卡。当用户点击某个按钮时，游戏将切换到相应的关卡。在游戏界面中，用户可以通过上下左右键来控制蛇的移动。当蛇吃到食物时，用户的得分将增加。如果蛇碰到墙壁或自己的身体，游戏将结束。

希望这个代码对您有所帮助。