ios __NSCFData

设置 header，

  AFHTTPClient *client = [[AFHTTPClient alloc]initWithBaseURL:[NSURL URLWithString:SERVER_TENCENT]];

    [client registerHTTPOperationClass:[AFJSONRequestOperationclass]];

    [client setDefaultHeader:@"Accept"value:@"application/json"];

    [client postPath:PATH_TENCENT_USERINFO parameters:parmas success:^(AFHTTPRequestOperation *operation, id responseObject) {