SpringBoot 并发登录人数控制的实现方法

public class CompareKickOutFilter extends KickOutFilter {

  @Autowired
  private UserService userService;

  @Override
  public boolean isAccessAllowed(HttpServletRequest request, HttpServletResponse response) {
    String token = request.getHeader("Authorization");
    String username = JWTUtil.getUsername(token);
    String userKey = PREFIX + username;

    RBucket<String> bucket = redissonClient.getBucket(userKey);
    String redisToken = bucket.get();

    if (token.equals(redisToken)) {
      return true;

    } else if (StringUtils.isBlank(redisToken)) {
      bucket.set(token);

    } else {
      Long redisTokenUnixTime = JWTUtil.getClaim(redisToken, "createTime").asLong();
      Long tokenUnixTime = JWTUtil.getClaim(token, "createTime").asLong();

      // token > redisToken 则覆盖
      if (tokenUnixTime.compareTo(redisTokenUnixTime) > 0) {
        bucket.set(token);

      } else {
        // 注销当前token
        userService.logout(token);
        sendJsonResponse(response, 4001, "您的账号已在其他设备登录");
        return false;

      }

    }

    return true;

  }
}

public class QueueKickOutFilter extends KickOutFilter {
  /**
   * 踢出之前登录的/之后登录的用户 默认踢出之前登录的用户
   */
  private boolean kickoutAfter = false;
  /**
   * 同一个帐号最大会话数 默认1
   */
  private int maxSession = 1;

  public void setKickoutAfter(boolean kickoutAfter) {
    this.kickoutAfter = kickoutAfter;
  }

  public void setMaxSession(int maxSession) {
    this.maxSession = maxSession;
  }

  @Override
  public boolean isAccessAllowed(HttpServletRequest request, HttpServletResponse response) throws Exception {
    String token = request.getHeader("Authorization");
    UserBO currentSession = CurrentUser.get();
    Assert.notNull(currentSession, "currentSession cannot null");
    String username = currentSession.getUsername();
    String userKey = PREFIX + "deque_" + username;
    String lockKey = PREFIX_LOCK + username;

    RLock lock = redissonClient.getLock(lockKey);

    lock.lock(2, TimeUnit.SECONDS);

    try {
      RDeque<String> deque = redissonClient.getDeque(userKey);

      // 如果队列里没有此token，且用户没有被踢出；放入队列
      if (!deque.contains(token) && currentSession.isKickout() == false) {
        deque.push(token);
      }

      // 如果队列里的sessionId数超出最大会话数，开始踢人
      while (deque.size() > maxSession) {
        String kickoutSessionId;
        if (kickoutAfter) { // 如果踢出后者
          kickoutSessionId = deque.removeFirst();
        } else { // 否则踢出前者
          kickoutSessionId = deque.removeLast();
        }

        try {
          RBucket<UserBO> bucket = redissonClient.getBucket(kickoutSessionId);
          UserBO kickoutSession = bucket.get();

          if (kickoutSession != null) {
            // 设置会话的kickout属性表示踢出了
            kickoutSession.setKickout(true);
            bucket.set(kickoutSession);
          }

        } catch (Exception e) {
        }

      }

      // 如果被踢出了，直接退出，重定向到踢出后的地址
      if (currentSession.isKickout()) {
        // 会话被踢出了
        try {
          // 注销
          userService.logout(token);
          sendJsonResponse(response, 4001, "您的账号已在其他设备登录");

        } catch (Exception e) {
        }

        return false;

      }

    } finally {
      if (lock.isHeldByCurrentThread()) {
        lock.unlock();
        LOGGER.info(Thread.currentThread().getName() + " unlock");

      } else {
        LOGGER.info(Thread.currentThread().getName() + " already automatically release lock");
      }
    }

    return true;
  }

}