AFNetWorking上传JSON串

AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
    manager.responseSerializer = [AFJSONResponseSerializer serializer];
    manager.requestSerializer=[AFJSONRequestSerializer serializer];
 
    [manager POST:urlStr parameters:parma progress:^(NSProgress * _Nonnull uploadProgress) {
 
    } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
        block(responseObject,nil);
 
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        [self showAlertView:[error description]];
        [self hideHud];
        block(nil,error);
    }];