用java写一个大鱼吃小鱼游戏

好的，以下是一个简单的 Java 大鱼吃小鱼游戏的示例代码：

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

public class FishGame extends JPanel implements KeyListener {
  
  private static final long serialVersionUID = 1L;
  private static final int FRAME_WIDTH = 500;
  private static final int FRAME_HEIGHT = 500;
  private static final int FISH_SIZE = 20;
  private static final int FOOD_SIZE = 10;
  private static final int NUM_FISH = 5;
  private static final int NUM_FOOD = 50;
  
  private List<Fish> fishList;
  private List<Food> foodList;
  private Fish playerFish;
  
  public FishGame() {
    JFrame frame = new JFrame("Fish Game");
    frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.addKeyListener(this);
    frame.add(this);
    frame.setVisible(true);
    
    fishList = new ArrayList<>();
    for (int i = 0; i < NUM_FISH; i++) {
      Fish fish = new Fish((int)(Math.random() * FRAME_WIDTH), 
                           (int)(Math.random() * FRAME_HEIGHT), 
                           FISH_SIZE);
      fishList.add(fish);
    }
    
    foodList = new ArrayList<>();
    for (int i = 0; i < NUM_FOOD; i++) {
      Food food = new Food((int)(Math.random() * FRAME_WIDTH), 
                           (int)(Math.random() * FRAME_HEIGHT), 
                           FOOD_SIZE);
      foodList.add(food);
    }
    
    playerFish = new Fish(FRAME_WIDTH / 2, FRAME_HEIGHT / 2, FISH_SIZE);
  }
  
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    
    for (Fish fish : fishList) {
      fish.draw(g);
    }
    
    for (Food food : foodList) {
      food.draw(g);
    }
    
    playerFish.draw(g);
  }
  
  public void keyPressed(KeyEvent e) {
    int keyCode = e.getKeyCode();
    if (keyCode == KeyEvent.VK_UP) {
      playerFish.moveUp();
    } else if (keyCode == KeyEvent.VK_DOWN) {
      playerFish.moveDown();
    } else if (keyCode == KeyEvent.VK_LEFT) {
      playerFish.moveLeft();
    } else if (keyCode == KeyEvent.VK_RIGHT) {
      playerFish.moveRight();
    }
    repaint();
  }
  
  public void keyTyped(KeyEvent e) {
    // Not used
  }
  
  public void keyReleased(KeyEvent e) {
    // Not used
  }
  
  public static void main(String[] args) {
    new FishGame();
  }
  
  private class Fish {
    private int x;
    private int y;
    private int size;
    
    public Fish(int x, int y, int size) {
      this.x = x;
      this.y = y;
      this.size = size;
    }
    
    public void draw(Graphics g) {
      g.setColor(Color.BLUE);
      g.fillOval(x, y, size, size);
    }
    
    public void moveUp() {
      y -= 10;
    }
    
    public void moveDown() {
      y += 10;
    }
    
    public void moveLeft() {
      x -= 10;
    }
    
    public void moveRight() {
      x += 10;
    }
    
    public int getX() {
      return x;
    }
    
    public int getY() {
      return y;
    }
    
    public int getSize() {
      return size;
    }
  }
  
  private class Food {
    private int x;
    private int y;
    private int size;
    
    public Food(int x, int y, int size) {
      this.x = x;
      this.y = y;
      this.size = size;
    }
    
    public void draw(Graphics g) {
      g.setColor(Color.GREEN);
      g.fillOval(x, y, size, size);
    }
    
    public int getX() {
      return x;
    }
    
    public int getY() {
      return y;
    }
    
    public int getSize() {
      return size;
    }
  }
}

这个示例代码中，我们使用 Java Swing 创建了一个窗口，并在窗口中绘制了一些小鱼和食物。玩家控制的大鱼可以通过键盘上下左右键来移动，吃掉小鱼和食物可以增加体积。你也可以根据自己的需求来修改代码以实现更多功能。