ios – AFNetworking 2.0在故障块中从代码400获取JSON

[operationManager POST:ServerURL parameters:parameters success:^(AFhttprequestOperation *operation,id responSEObject) {
    NSLog(@"success: Status Code: %d",operation.response.statusCodE);
}
 failure:^(AFhttprequestOperation *operation,NSError *error) {
     NSLog(@"Failed: Status Code: %d",operation.response.statusCodE);
 }];

不传递响应对象,如成功块中的响应对象.那么有谁知道如何访问Web服务返回的带有400错误的JSON？ NSError *错误只是让我失败：错误的请求(400)而不是返回的JSON.

任何帮助将不胜感激,迈克