Spring Boot + Vue 实战：基于 WebSocket 的实时对战匹配系统

建立 WebSocket 连接

在 PKIndex.vue 组件挂载时初始化连接。注意生命周期钩子的配合，卸载时务必断开连接以防资源泄漏。

<!-- views/pk/PKIndex.vue -->
<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>

至此，前端与后端即可通过 WebSocket 互相连接。

安全性升级：JWT 验证

直接用 userId 拼接 URL 存在安全风险，用户可伪装身份。建议改用 JWT Token。

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

后端解析 Token 获取用户 ID，若无效则直接关闭会话。

// 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;
    }
}

修改后端 WebSocketServer.java 中的 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(); // 验证失败直接关闭
    }
}

后端匹配逻辑

使用 ConcurrentHashMap 存储在线用户，CopyOnWriteArraySet 作为匹配池。当池中人数达到 2 人，立即生成游戏地图并通知双方。

// consumer/WebSocketServer.java
@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() {
        System.out.println("disconnected!");
        if (this.user != null) {
            users.remove(this.user.getId());
            matchpool.remove(this.user);
        }
    }

    private void startMatching() {
        System.out.println("start matching!");
        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() {
        System.out.println("stop matching");
        matchpool.remove(this.user);
    }

    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("receive message!");
        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();
            }
        }
    }
}

游戏地图生成

后端需同步生成游戏地图数据。这里采用 DFS 算法确保迷宫连通性。

// 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;
        }
    }
}

前后端联调

前端收到 start-matching 事件后，更新对手信息并切换视图状态。

<!-- views/PKIndex.vue -->
<template>
  <PlayGround v-if="$store.state.pk.status === 'playing'"/>
  <MatchGround v-if="$store.state.pk.status === 'matching'"/>
</template>
<script>
import PlayGround from '@/components/PlayGround.vue';
import MatchGround from '@/components/MatchGround.vue';
import { onMounted, onUnmounted } from 'vue'
import { useStore } from 'vuex'

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

    onMounted(() => {
      store.commit("updateOpponent", {
        username: "我的对手",
        photo: "https://cdn.acwing.com/media/article/image/2022/08/09/1_1db2488f17-anonymous.png"
      });
      socket = new WebSocket(socketUrl);
      socket.onopen = () => {
        console.log("connected!");
        store.commit("updateSocket", socket);
      }
      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);
        }
      }
      socket.onclose = () => {
        console.log("disconnected!");
      }
    });

    onUnmounted(() => {
      socket.close();
      store.commit("updateStatus", "matching");
    })
  }
}
</script>

这样我们就完成了一个基础的实时对战匹配闭环。实际开发中，还需考虑断线重连、心跳检测等细节，但核心链路已清晰呈现。