package com.hh.utils; import java.awt.*; import java.lang.reflect.Field; public class GameUtils { //蛇头 public static Image upImg=Toolkit.getDefaultToolkit().getImage("img/up.png"); public static Image downImg=Toolkit.getDefaultToolkit().getImage("img/down.png"); public static Image leftImg=Toolkit.getDefaultToolkit().getImage("img/left.png"); public static Image rightImg=Toolkit.getDefaultToolkit().getImage("img/right.png"); //蛇身 public static Image bodyImg=Toolkit.getDefaultToolkit().getImage("img/body.png"); //食物 public static Image foodImg=Toolkit.getDefaultToolkit().getImage("img/food.png"); //关卡 public static int level= 1; //绘制文字 public static void drawWord(Graphics g,String str,Color color,int size,int x,int y){ g.setColor(color); g.setFont(new Font("宋体",Font.BOLD,size)); g.drawString(str, x, y); } } 将这段代码用反射机制改写

反射机制可以动态地获取类的信息并调用其方法或访问其属性。下面是使用反射机制重写的代码：

package com.hh.utils;

import java.awt.*;
import java.lang.reflect.Field;

public class GameUtils {

    //蛇头
    public static Image upImg;
    public static Image downImg;
    public static Image leftImg;
    public static Image rightImg;

    //蛇身
    public static Image bodyImg;

    //食物
    public static Image foodImg;

    //关卡
    public static int level = 1;

    //绘制文字
    public static void drawWord(Graphics g, String str, Color color, int size, int x, int y) {
        g.setColor(color);
        g.setFont(new Font("宋体", Font.BOLD, size));
        g.drawString(str, x, y);
    }

    static {
        try {
            Class<?> clazz = GameUtils.class;
            Field upImgField = clazz.getDeclaredField("upImg");
            upImgField.setAccessible(true);
            upImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/up.png"));

            Field downImgField = clazz.getDeclaredField("downImg");
            downImgField.setAccessible(true);
            downImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/down.png"));

            Field leftImgField = clazz.getDeclaredField("leftImg");
            leftImgField.setAccessible(true);
            leftImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/left.png"));

            Field rightImgField = clazz.getDeclaredField("rightImg");
            rightImgField.setAccessible(true);
            rightImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/right.png"));

            Field bodyImgField = clazz.getDeclaredField("bodyImg");
            bodyImgField.setAccessible(true);
            bodyImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/body.png"));

            Field foodImgField = clazz.getDeclaredField("foodImg");
            foodImgField.setAccessible(true);
            foodImgField.set(null, Toolkit.getDefaultToolkit().getImage("img/food.png"));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用静态代码块，我们可以在类加载时通过反射机制动态地设置类中的静态属性。这样，就可以实现和原代码相同的功能，但是更加灵活和可扩展。