Spring Boot 前后端实时匹配系统设计与实现

前言

在现代 Web 开发中，前端和后端的协作至关重要，特别是在需要实时交互和数据更新的应用场景中。WebSocket 技术作为一种全双工通信协议，使得前端和后端之间的实时数据传输变得更加高效和稳定。本文探讨如何设计和实现一个实时匹配系统，其中前端负责展示用户界面并与后端进行交互，而后端则通过 WebSocket 协议来处理数据通信。

前端状态管理

Vuex Store 配置

在 store/pk.js 中定义匹配相关状态：

import ModuleUser from './user'
export default {
  state: {
    socket: null, // ws 链接
    opponent_username: "",
    opponent_photo: "",
    status: "matching", // matching 表示匹配界面，playing 表示对战界面
  },
  getters: {},
  mutations: {
    updateSocket(state, socket) { state.socket = socket; },
    updateOpponent(state, opponent) { 
      state.opponent_username = opponent.username; 
      state.opponent_photo = opponent.photo;
    },
    updateStatus(state, status) { state.status = status; }
  },
  actions: {},
  modules: { user: ModuleUser }
}

在 store/index.js 中引入模块：

import { createStore } from 'vuex'
import ModuleUser from './user'
import ModulePk from './pk'
export default createStore({
  state: {},
  getters: {},
  mutations: {},
  actions: {},
  modules: { user: ModuleUser, pk: ModulePk }
})

建立 WebSocket 连接

在 views/pk/PKIndex.vue 中使用 Vue 3 Composition API 建立连接：

<template>
  <PlayGround/>
</template>
<script>
import PlayGround from '@/components/PlayGround.vue'
import { onMounted, onUnmounted } from 'vue'
import { useStore } from 'vuex'

export default {
  name: "PKindex",
  components: { PlayGround },
  setup() {
    const store = useStore()
    const socketUrl = `ws://127.0.0.1:3000/websocket/${store.state.user.id}/`
    let socket = null

    onMounted(() => {
      socket = new WebSocket(socketUrl)
      socket.onopen = () => {
        console.log("connected!")
        store.commit("updateSocket", socket)
      }
      socket.onmessage = msg => {
        const data = JSON.parse(msg.data)
        console.log(data)
      }
      socket.onclose = () => {
        console.log("disconnected!")
      }
    })

    onUnmounted(() => {
      if (socket) socket.close()
    })
  }
}
</script>
<style scoped></style>

JWT 身份验证

若使用 userId 建立 ws 连接，用户可伪装成任意用户，因此不安全。应使用 token 进行验证。

修改连接 URL：

const socketUrl = `ws://127.0.0.1:3000/websocket/${store.state.user.token}/`;

后端添加 JWT 验证逻辑 consumer/utils/JwtAuthentication.java：

package org.example.backend.consumer.utils;
import io.jsonwebtoken.Claims;
import org.example.backend.utils.JwtUtil;

public class JwtAuthentication {
    public static Integer getUserId(String token) {
        int userId = -1;
        try {
            Claims claims = JwtUtil.parseJWT(token);
            userId = Integer.parseInt(claims.getSubject());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return userId;
    }
}

修改 consumer/WebSocketServer.java 的 onOpen 方法：

@OnOpen
public void onOpen(Session session, @PathParam("token") String token) throws IOException {
    this.session = session;
    System.out.println("connected to websocket");
    Integer userId = JwtAuthentication.getUserId(token);
    User user = userMapper.selectById(userId);
    if (user != null) {
        users.put(userId, this);
    } else {
        this.session.close();
    }
}

匹配界面与对战界面切换

在 views/pk/PKindexView.vue 中根据状态渲染不同组件：

<template>
  <PlayGround v-if="$store.state.pk.status === 'playing'"/>
  <MatchGround v-if="$store.state.pk.status === 'matching'"/>
</template>

创建匹配页面组件 components/MatchGround.vue：

<template>
  <div class="matchground">
    <div class="row">
      <div class="col-6">
        <div class="user-photo"><img :src="$store.state.user.photo" alt=""></div>
        <div class="user-username">{{ $store.state.user.username }}</div>
      </div>
      <div class="col-6">
        <div class="user-photo"><img :src="$store.state.pk.opponent_photo" alt=""></div>
        <div class="user-username">{{ $store.state.pk.opponent_username }}</div>
      </div>
      <div class="col-12" style="text-align: center; padding-top: 15vh;">
        <button @click="click_match_btn" type="button" class="btn btn-warning btn-lg">{{ match_btn_info }}</button>
      </div>
    </div>
  </div>
</template>
<script>
import { ref } from 'vue'
import { useStore } from 'vuex';

export default {
  setup() {
    const store = useStore();
    let match_btn_info = ref("开始匹配");
    const click_match_btn = () => {
      if (match_btn_info.value === "开始匹配") {
        match_btn_info.value = "取消";
        store.state.pk.socket.send(JSON.stringify({ event: "start-matching", }));
      } else {
        match_btn_info.value = "开始匹配";
        store.state.pk.socket.send(JSON.stringify({ event: "stop-matching", }));
      }
    }
    return { match_btn_info, click_match_btn };
  }
}
</script>
<style scoped>
div.matchground { width: 60vw; height: 70vh; margin: 40px auto; background-color: rgba(50,50,50,0.5); }
div.user-photo { text-align: center; padding-top: 10vh; }
div.user-photo>img { border-radius: 50%; width: 20vh; }
div.user-username { text-align: center; font-size: 24px; font-weight: 600; color: white; padding-top: 2vh; }
</style>

后端匹配逻辑

consumer/WebSocketServer.java 核心实现：

@Component
@ServerEndpoint("/websocket/{token}")
public class WebSocketServer {
    private final static ConcurrentHashMap<Integer, WebSocketServer> users = new ConcurrentHashMap<>();
    private final static CopyOnWriteArraySet<User> matchpool = new CopyOnWriteArraySet<>();
    private User user;
    private Session session = null;
    private static UserMapper userMapper;

    @Autowired
    public void setUserMapper(UserMapper userMapper) {
        WebSocketServer.userMapper = userMapper;
    }

    @OnOpen
    public void onOpen(Session session, @PathParam("token") String token) throws IOException {
        this.session = session;
        Integer userId = JwtAuthentication.getUserId(token);
        this.user = userMapper.selectById(userId);
        if (this.user != null) {
            users.put(userId, this);
        } else {
            this.session.close();
        }
    }

    @OnClose
    public void onClose() {
        if (this.user != null) {
            users.remove(this.user.getId());
            matchpool.remove(this.user);
        }
    }

    private void startMatching() {
        matchpool.add(this.user);
        while (matchpool.size() >= 2) {
            Iterator<User> it = matchpool.iterator();
            User a = it.next(), b = it.next();
            matchpool.remove(a);
            matchpool.remove(b);
            Game game = new Game(13, 14, 20);
            game.createMap();
            JSONObject respA = new JSONObject();
            respA.put("event", "start-matching");
            respA.put("opponent_username", b.getUsername());
            respA.put("opponent_photo", b.getPhoto());
            respA.put("gamemap", game.getG());
            users.get(a.getId()).sendMessage(respA.toJSONString());

            JSONObject respB = new JSONObject();
            respB.put("event", "start-matching");
            respB.put("opponent_username", a.getUsername());
            respB.put("opponent_photo", a.getPhoto());
            respB.put("gamemap", game.getG());
            users.get(b.getId()).sendMessage(respB.toJSONString());
        }
    }

    private void stopMatching() {
        matchpool.remove(this.user);
    }

    @OnMessage
    public void onMessage(String message, Session session) {
        JSONObject data = JSONObject.parseObject(message);
        String event = data.getString("event");
        if ("start-matching".equals(event)) {
            startMatching();
        } else if ("stop-matching".equals(event)) {
            stopMatching();
        }
    }

    @OnError
    public void onError(Session session, Throwable error) {
        error.printStackTrace();
    }

    public void sendMessage(String message) {
        synchronized (this.session) {
            try {
                this.session.getBasicRemote().sendText(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

前端接收消息并处理：

socket.onmessage = msg => {
    const data = JSON.parse(msg.data);
    if (data.event === "start-matching") {
        store.commit("updateOpponent", {
            username: data.opponent_username,
            photo: data.opponent_photo,
        });
        setTimeout(() => {
            store.commit("updateStatus", "playing");
        }, 2000);
        store.commit("updateGamemap", data.gamemap);
    }
};

地图生成算法

后端创建 Game 类实现游戏流程，使用深度优先搜索（DFS）算法检查地图连通性。

consumer/utils/Game.java：

package org.example.backend.consumer.utils;
import java.util.Random;

public class Game {
    private final Integer rows;
    private final Integer cols;
    private final Integer inner_walls_count;
    private final int[][] g;
    private final static int[] dx = {-1, 0, 1, 0}, dy = {0, 1, 0, -1};

    public Game(Integer rows, Integer cols, Integer inner_walls_count) {
        this.rows = rows;
        this.cols = cols;
        this.inner_walls_count = inner_walls_count;
        this.g = new int[rows][cols];
    }

    public int[][] getG() { return g; }

    private boolean check_connectivity(int sx, int sy, int tx, int ty) {
        if (sx == tx && sy == ty) return true;
        g[sx][sy] = 1;
        for (int i = 0; i < 4; i++) {
            int x = sx + dx[i], y = sy + dy[i];
            if (x >= 0 && x < this.rows && y >= 0 && y < this.cols && g[x][y] == 0) {
                if (check_connectivity(x, y, tx, ty)) {
                    g[sx][sy] = 0;
                    return true;
                }
            }
        }
        g[sx][sy] = 0;
        return false;
    }

    private boolean draw() {
        for (int i = 0; i < this.rows; i++) {
            for (int j = 0; j < this.cols; j++) {
                g[i][j] = 0;
            }
        }
        for (int r = 0; r < this.rows; r++) {
            g[r][0] = g[r][this.cols - 1] = 1;
        }
        for (int c = 0; c < this.cols; c++) {
            g[0][c] = g[this.rows - 1][c] = 1;
        }
        Random random = new Random();
        for (int i = 0; i < this.inner_walls_count / 2; i++) {
            for (int j = 0; j < 1000; j++) {
                int r = random.nextInt(this.rows);
                int c = random.nextInt(this.cols);
                if (g[r][c] == 1 || g[this.rows - 1 - r][this.cols - 1 - c] == 1) continue;
                if (r == this.rows - 2 && c == 1 || r == 1 && c == this.cols - 2) continue;
                g[r][c] = g[this.rows - 1 - r][this.cols - 1 - c] = 1;
                break;
            }
        }
        return check_connectivity(this.rows - 2, 1, 1, this.cols - 2);
    }

    public void createMap() {
        for (int i = 0; i < 1000; i++) {
            if (draw()) break;
        }
    }
}

总结

本文介绍了如何使用 WebSocket 实现前端与后端的实时匹配。前端通过 Vuex 管理状态，动态渲染匹配或对战界面；后端利用 WebSocket Server 处理连接、验证及匹配池逻辑。双方通过事件驱动保持数据同步，确保实时交互体验。