设置AFN请求&返回格式

    AFHTTPSessionManager *manager =[AFHTTPSessionManager manager];
    /**
     /// 请求格式
     AFHTTPRequestSerializer            二进制格式
     AFJSONRequestSerializer            JSON
     AFPropertyListRequestSerializer    PList（是一种特殊的XML，解析起来相对容易）
     */
    /// 二进制格式
    AFHTTPRequestSerializer *httpReqe = [AFHTTPRequestSerializer serializer];
    /// JSON
    AFJSONRequestSerializer *jsonReqe = [AFJSONRequestSerializer serializer];
    /// PList（是一种特殊的XML，解析起来相对容易）
    AFPropertyListRequestSerializer *plistReqe = [AFPropertyListRequestSerializer serializer];
    /// 设置请求格式
    manager.requestSerializer = jsonReqe;
    
    /**
     AFHTTPResponseSerializer           二进制格式
     AFJSONResponseSerializer           JSON
     AFXMLParserResponseSerializer      XML,只能返回XMLParser,还需要自己通过代理方法解析
     AFXMLDocumentResponseSerializer    (Mac OS X)
     AFPropertyListResponseSerializer   PList
     AFImageResponseSerializer          Image
     AFCompoundResponseSerializer       组合
     */
    /// 返回格式
    /// 二进制格式
    AFHTTPResponseSerializer *httpResp = [AFHTTPResponseSerializer serializer];
    /// JSON
    AFJSONResponseSerializer *jsonResp = [AFJSONResponseSerializer serializer];
    /// XML
    AFXMLParserResponseSerializer *xmlResp = [AFXMLParserResponseSerializer serializer];
    /// PList
    AFPropertyListResponseSerializer *plistResp = [AFPropertyListResponseSerializer serializer];
    /// Image
    AFImageResponseSerializer *imgResp = [AFImageResponseSerializer serializer];
    /// 组合
    AFCompoundResponseSerializer *compResp = [AFCompoundResponseSerializer serializer];
    /// 设置返回格式
    manager.responseSerializer = jsonReqe;
    
    [manager POST:urlStr parameters:params progress:^(NSProgress * _Nonnull downloadProgress) {
        // 进度
    } success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
        // 请求成功
        !success ?: success(responseObject);
    } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
        // 请求失败
        !failure ?: failure(error);
    }];