GUI学习完整文件地址https://github.com/asako98/gui-study.git

import javax.swing.*;

//游戏的主启动类
public class StartGame {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setBounds(10,10,900,720);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        //正常的游戏界面都应该在面板上
        frame.add(new GamePanel());
        frame.setVisible(true);
    }
}

import javax.swing.*;
import java.net.URL;

//数据中心
public class Data {
    public static URL headerURL = Data.class.getResource("/statics/header.png");
    public static ImageIcon header = new ImageIcon(headerURL);
    public static URL upURL = Data.class.getResource("/statics/up.png");
    public static URL downURL = Data.class.getResource("/statics/down.png");
    public static URL LeftURL = Data.class.getResource("/statics/left.png");
    public static URL rightURL = Data.class.getResource("/statics/right.png");
    public static ImageIcon up = new ImageIcon(upURL);
    public static ImageIcon down = new ImageIcon(downURL);
    public static ImageIcon Left = new ImageIcon(LeftURL);
    public static ImageIcon right = new ImageIcon(rightURL);

    public static URL bodyURL = Data.class.getResource("/statics/body.png");
    public static ImageIcon body = new ImageIcon(bodyURL);

    public static URL foodURL = Data.class.getResource("/statics/food.png");
    public static ImageIcon food = new ImageIcon(foodURL);
}

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;

public class GamePanel extends JPanel implements KeyListener,ActionListener {
    //定义蛇的数据结构
    int length;//蛇的长度
    int[] snakeX = new int[600];//蛇的x坐标 25*25
    int[] snakeY = new int[500];//蛇的y坐标 25*25
    String fx ;//初始方向
    //食物的坐标
    int foodx;
    int foody;
    Random random = new Random();
    int score;//成绩
    //游戏当前的状态： 开始，停止
    boolean isStart =false;//默认是不开始的
    boolean isFail = false;//游戏失败状态
    //定时器，以毫秒为单位，1000ms=1s
    Timer timer = new Timer(100,this);//100毫秒执行一次
    //构造器
    public GamePanel() {
        init();
        //获得焦点和键盘事件
        this.setFocusable(true);//获取焦点事件
        this.addKeyListener(this);//获得键盘监听事件
        timer.start();//游戏一开始定时器就启动
    }

    //初始化方法
    public void init(){
        length = 3;
        snakeX[0] = 100;snakeY[0] = 100;//脑袋的坐标
        snakeX[1] = 75;snakeY[1] = 100;//第一个身体的坐标
        snakeX[2] = 50;snakeY[2] = 100;//第二个身体的坐标
        fx="R";//初始方向向右
        //把食物随机分布在界面上
        foodx=25+25*random.nextInt(34);
        foody=75+75*random.nextInt(24);
        score=0;
    }
    //绘制面板，游戏中的所有东西都使用这个画笔来画
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);//清屏
        //绘制静态的面板

        this.setBackground(Color.white);
        Data.header.paintIcon(this,g,25,11);//头部广告栏画上去
        g.fillRect(25,75,850,600);//默认的游戏界面

        //把小蛇画上去
        if(fx.equals("R")){
            Data.right.paintIcon(this,g,snakeX[0],snakeY[0]);//蛇头初始化向右，需要通过方向来判断
        }else if(fx.equals("L")){
            Data.Left.paintIcon(this,g,snakeX[0],snakeY[0]);//蛇头初始化向左，需要通过方向来判断
        }else if(fx.equals("U")){
            Data.up.paintIcon(this,g,snakeX[0],snakeY[0]);//蛇头初始化向上，需要通过方向来判断
        }else if(fx.equals("D")){
            Data.down.paintIcon(this,g,snakeX[0],snakeY[0]);//蛇头初始化向下，需要通过方向来判断
        }

        for (int i = 1; i < length; i++) {
            Data.body.paintIcon(this,g,snakeX[i],snakeY[i]);
        }
        //画积分
        g.setColor(Color.white);
        g.setFont(new Font("微软雅黑",Font.BOLD,18));
        g.drawString("长度"+length,750,35);
        g.drawString("分数"+score,750,50);
        //画食物
        Data.food.paintIcon(this,g,foodx,foody);
        //游戏状态
        if(isStart==false){
            g.setColor(Color.white);
            g.setFont(new Font("微软雅黑",Font.BOLD,40));
            g.drawString("按下空格开始游戏",300,300);
        }
         if(isFail){
            g.setColor(Color.red);
             g.setFont(new Font("微软雅黑",Font.BOLD,40));
             g.drawString("失败，按下空格重新开始",300,300);
         }
    }



    //键盘监听事件
    @Override
    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();//获得键盘按键是哪一个
        if(keyCode==KeyEvent.VK_SPACE){//如果按下的是空格键
            if(isFail){
                //重新开始
                isFail=false;
                init();
            }else{
                isStart = !isStart;
            }
            repaint();
        }
       //小蛇移动
        if(keyCode==KeyEvent.VK_UP){
            fx="U";
        }else if(keyCode==KeyEvent.VK_LEFT){
            fx="L";
        }else if(keyCode==KeyEvent.VK_RIGHT){
            fx="R";
        }else if(keyCode==KeyEvent.VK_DOWN){
            fx="D";
        }
    }
    @Override
    public void keyTyped(KeyEvent e) {

    }
    @Override
    public void keyReleased(KeyEvent e) {

    }
    //事件监听，需要通过固定时间来刷新
    @Override
    public void actionPerformed(ActionEvent e) {
        if(isStart&&isFail==false){//如果游戏是开始状态，就让小蛇动起来
            //吃食物
            if(snakeX[0]==foodx&&snakeY[0]==foody){
                length++;
                //分数+10
                score=score+10;
                //再次随机食物
                foodx=25+25*random.nextInt(34);
                foody=75+75*random.nextInt(24);
            }
            //移动
            for(int i=length-1;i>0;i--){
                snakeX[i] = snakeX[i-1];
                snakeY[i] = snakeY[i-1];
            }
            //走向
            if(fx.equals("R")){
                snakeX[0] = snakeX[0]+25;
                if(snakeX[0]>850){ snakeX[0]=25; }//边界判断
            }else if(fx.equals("L")) {
                snakeX[0] = snakeX[0] - 25;
                if (snakeX[0] < 25) { snakeX[0] = 850; }
            }else if(fx.equals("U")){
                snakeY[0] = snakeY[0]-25;
                if(snakeY[0]<75){snakeY[0]=650;}
            }else if(fx.equals("D")){
                snakeY[0] = snakeY[0]+25;
                if(snakeY[0]>650){snakeY[0]=75;}
            }

            //失败判断，撞到自己算失败
            for (int i = 1; i < length; i++) {
                if(snakeX[0]==snakeX[i]&&snakeY[0]==snakeY[i]){
                    isFail=true;
                }
            }

            repaint();//重画
        }
        timer.start();//定时器开启
    }
}