用Java编写一个俄罗斯方块游戏

好的，下面是一个简单的Java实现俄罗斯方块游戏的示例代码：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Tetris extends JPanel implements KeyListener {
  private static final long serialVersionUID = 1L;
  private final int SIZE = 20; // 方格大小
  private final int WIDTH = 10; // 游戏区宽度
  private final int HEIGHT = 20; // 游戏区高度
  private int[][] board = new int[HEIGHT][WIDTH]; // 游戏区矩阵
  private int[][][] shapes = { // 七种不同形状的方块
      { { 1, 1, 1, 1 } }, 
      { { 1, 1, 0 }, { 0, 1, 1 } }, 
      { { 0, 1, 1 }, { 1, 1, 0 } }, 
      { { 1, 0, 0 }, { 1, 1, 1 } },
      { { 0, 0, 1 }, { 1, 1, 1 } }, 
      { { 1, 1 }, { 1, 1 } }, 
      { { 0, 1, 0 }, { 1, 1, 1 } } };
  private Color[] colors = { // 每种方块的颜色
      Color.cyan, Color.blue, Color.orange, Color.yellow, Color.green, Color.pink, Color.red };
  private int[][] shape; // 当前方块
  private int shapeType; // 当前方块类型
  private int shapeX, shapeY; // 当前方块位置
  private boolean gameOver; // 游戏是否结束

  public Tetris() {
    setPreferredSize(new java.awt.Dimension(WIDTH * SIZE, HEIGHT * SIZE));
    setBackground(Color.black);
    addKeyListener(this);
    newGame();
  }

  private void newGame() {
    for (int i = 0; i < HEIGHT; i++) {
      for (int j = 0; j < WIDTH; j++) {
        board[i][j] = 0;
      }
    }
    gameOver = false;
    newShape();
    repaint();
  }

  private void newShape() {
    shapeType = (int) (Math.random() * shapes.length);
    shape = shapes[shapeType];
    shapeX = WIDTH / 2 - shape[0].length / 2;
    shapeY = 0;
    if (collision()) {
      gameOver = true;
    }
  }

  private boolean collision() {
    for (int i = 0; i < shape.length; i++) {
      for (int j = 0; j < shape[i].length; j++) {
        if (shape[i][j] != 0 && (shapeY + i >= HEIGHT || shapeX + j < 0 || shapeX + j >= WIDTH || board[shapeY + i][shapeX + j] != 0)) {
          return true;
        }
      }
    }
    return false;
  }

  private void merge() {
    for (int i = 0; i < shape.length; i++) {
      for (int j = 0; j < shape[i].length; j++) {
        if (shape[i][j] != 0) {
          board[shapeY + i][shapeX + j] = shapeType + 1;
        }
      }
    }
    checkLines();
    newShape();
  }

  private void checkLines() {
    for (int i = HEIGHT - 1; i >= 0; i--) {
      boolean full = true;
      for (int j = 0; j < WIDTH; j++) {
        if (board[i][j] == 0) {
          full = false;
        }
      }
      if (full) {
        for (int k = i; k > 0; k--) {
          for (int j = 0; j < WIDTH; j++) {
            board[k][j] = board[k - 1][j];
          }
        }
        i++;
      }
    }
  }

  private void moveDown() {
    shapeY++;
    if (collision()) {
      shapeY--;
      merge();
    }
    repaint();
  }

  private void moveLeft() {
    shapeX--;
    if (collision()) {
      shapeX++;
    }
    repaint();
  }

  private void moveRight() {
    shapeX++;
    if (collision()) {
      shapeX--;
    }
    repaint();
  }

  private void rotate() {
    int[][] newShape = new int[shape[0].length][shape.length];
    for (int i = 0; i < shape.length; i++) {
      for (int j = 0; j < shape[i].length; j++) {
        newShape[j][shape.length - 1 - i] = shape[i][j];
      }
    }
    shape = newShape;
    if (collision()) {
      shape = new int[][] { { 1, 1, 1, 1 } };
    }
    repaint();
  }

  @Override
  public void keyTyped(KeyEvent e) {
  }

  @Override
  public void keyPressed(KeyEvent e) {
    switch (e.getKeyCode()) {
    case KeyEvent.VK_UP:
      rotate();
      break;
    case KeyEvent.VK_DOWN:
      moveDown();
      break;
    case KeyEvent.VK_LEFT:
      moveLeft();
      break;
    case KeyEvent.VK_RIGHT:
      moveRight();
      break;
    case KeyEvent.VK_SPACE:
      while (!collision()) {
        moveDown();
      }
      moveDown();
      break;
    case KeyEvent.VK_ENTER:
      if (gameOver) {
        newGame();
      }
      break;
    }
  }

  @Override
  public void keyReleased(KeyEvent e) {
  }

  @Override
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    for (int i = 0; i < HEIGHT; i++) {
      for (int j = 0; j < WIDTH; j++) {
        if (board[i][j] != 0) {
          g.setColor(colors[board[i][j] - 1]);
          g.fillRect(j * SIZE, i * SIZE, SIZE, SIZE);
        }
      }
    }
    if (!gameOver) {
      g.setColor(colors[shapeType]);
      for (int i = 0; i < shape.length; i++) {
        for (int j = 0; j < shape[i].length; j++) {
          if (shape[i][j] != 0) {
            g.fillRect((shapeX + j) * SIZE, (shapeY + i) * SIZE, SIZE, SIZE);
          }
        }
      }
    } else {
      g.setColor(Color.white);
      g.drawString("GAME OVER", WIDTH * SIZE / 2 - 30, HEIGHT * SIZE / 2 - 10);
      g.drawString("Press ENTER to start a new game", WIDTH * SIZE / 2 - 80, HEIGHT * SIZE / 2 + 10);
    }
  }

  public static void main(String[] args) {
    JFrame frame = new JFrame("Tetris");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setLocationRelativeTo(null);
    frame.add(new Tetris());
    frame.pack();
    frame.setVisible(true);
  }
}

这个代码会在一个游戏窗口中实现俄罗斯方块游戏，你可以通过上下左右箭头键来控制方块的移动和旋转，按空格键可以快速下落，按回车键可以重新开始游戏。