dispatch_semaphore_t semaphore = dispatch_semaphore_create(0); //创建信号量

    AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];

    manager.requestSerializer.timeoutInterval = 5;

    manager.completionQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    //如果之前请求有值，则异步就好，不然会卡主线程

    if([OverallModel shareOverallModel].nSystemParameter){

        dispatch_semaphore_signal(semaphore);

    }

    [manager GET:[AppURLRequest getSystemVekey] parameters:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, NSDictionary *responseObject) {

         dispatch_semaphore_signal(semaphore);//不管请求状态是什么，都得发送信号，否则会一直卡着进程

         NSInteger result = [[NSString stringWithFormat:@"%@",[responseObject objectForKey:@"result"]]integerValue];

        if(result == 1){

            NSString *nSystemParameter = NSZL(responseObject[@"data"][@"nSystemParameter"]);

            NSString *QQInfo = NSZL(responseObject[@"data"][@"QQInfo"]);

            [OverallModel shareOverallModel].nSystemParameter = nSystemParameter;

            [OverallModel shareOverallModel].QQInfo = QQInfo;

        }

    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {

        dispatch_semaphore_signal(semaphore);//不管请求状态是什么，都得发送信号，否则会一直卡着进程

    }];

    dispatch_semaphore_wait(semaphore,DISPATCH_TIME_FOREVER);  //等待