virtual-patient/virtual-patient-web/src/main/java/com/supervision/controller/WebSocketServer.java

package com.supervision.controller;

import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONUtil;
import com.supervision.constant.UserTokenConstant;
import com.supervision.usermanage.UserWebSocketDTO;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;

@Component
@Slf4j
@ServerEndpoint("/webSocket/{uid}")
public class WebSocketServer {

    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    //concurrent包的线程安全Set，用来存放每个客户端对应的WebSocketServer对象。
    private static final ConcurrentHashMap<String, Session> SESSION_POOL = new ConcurrentHashMap<>();

    /**
     * 有客户端连接成功
     */
    @OnOpen
    public void onOpen(Session session, @PathParam(value = "uid") String uid) throws IOException {
        log.info("用户:{}登录,缓存到Redis", uid);
        // 链接之前先把之前的用户踢下线(ignoreSessionId防止把当前用户踢下线)
        redisTemplate.convertAndSend(UserTokenConstant.KICK_CHANNEL, JSONUtil.toJsonStr(new UserWebSocketDTO(uid, session.getId())));
        SESSION_POOL.put(uid, session);
        redisTemplate.opsForHash().put(UserTokenConstant.USER_ID_CACHE, uid, session.getId());
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose(Session session, @PathParam(value = "uid") String uid) {
        redisTemplate.opsForHash().delete(UserTokenConstant.USER_ID_CACHE, uid, session.getId());
        SESSION_POOL.remove(uid);
        log.info("用户:{}关闭，从Redis中移除,当前连接数为：{}", uid, redisTemplate.opsForHash().size(UserTokenConstant.USER_ID_CACHE));
    }

    /**
     * 发生错误
     */
    @OnError
    public void onError(Session session, @PathParam(value = "uid") String uid, Throwable throwable) {
        redisTemplate.opsForHash().delete(UserTokenConstant.USER_ID_CACHE, uid, session.getId());
        SESSION_POOL.remove(uid);
        log.error("用户:{}发生错误，从Redis中移除,当前连接数为：{}", uid, redisTemplate.opsForHash().size(UserTokenConstant.USER_ID_CACHE), throwable);
    }

    // 实现一个方法用于踢下线用户,走的是Redis的消息队列
    public void kickUser(String userId, String ignoreSessionId) throws IOException {
        log.info("尝试主动踢用户:{}下线", userId);
        Session session = SESSION_POOL.get(userId);
        // 只有不是忽略剔除的sessionId才可以踢下线
        if (ObjectUtil.isNotEmpty(session) && !StrUtil.equals(ignoreSessionId, session.getId())) {
            session.close(new CloseReason(CloseReason.CloseCodes.NORMAL_CLOSURE, "用户被踢下线"));
            SESSION_POOL.remove(userId);
            log.info("主动踢用户:{},sessionId:{} 下线成功", userId, session.getId());
            return;
        }
        log.info("主动踢用户:{}下线,未找到用户,踢下线失败", userId);
    }
}