Ios 基于afp网络的JSON解析

我试图从web api捕获JSON请求。当我从服务器获得JSON格式的响应时，我将以NSData格式而不是NSDictionnary格式接收响应。我从本教程（RESTful类段落）中得到启发，通过AFJSONRequestOperation更改客户机的注册操作类，从而实现免费的JSON解析。但是，它不起作用，我仍然得到NSData格式的响应

{"uid":"98545931","token":"98545931:176:ec0b862ba57fef88394950dd0cc41491"}

编辑：以下是完整的错误消息：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFData objectForKey:]: unrecognized selector sent to instance 0x753aa00'

{"uid":"98545931","token":"98545931:176:ec0b862ba57fef88394950dd0cc41491"}

以下是服务器的响应：

{"uid":"98545931","token":"98545931:176:ec0b862ba57fef88394950dd0cc41491"}

有人知道为什么不能自动解析吗

{"uid":"98545931","token":"98545931:176:ec0b862ba57fef88394950dd0cc41491"}

AFHTTPClient *client = [[AFHTTPClient alloc] initWithBaseURL:baseurl];
//Here, we tell the AFHTTPClient that the server is responding to us in JSON format.
[client registerHTTPOperationClass:[AFJSONRequestOperation class]];

//Creating the dictionary containing the post parameters.
NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:username, @"username", password, @"password", nil];


//AUTHENTIFICATION. Retrieving token and uid by POST method.
[client postPath:@"/auth" parameters:params
         success:^(AFHTTPRequestOperation *operation, id responseObject)
{
    NSString *text = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
    NSLog(@"Response: %@", text);
    [responseField setText:text];
    self.jsonResponse = responseObject;

    //The NSJSONSerialization method to transform the NSData responseObject into a dictionnary does work
    self.jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:0 error:nil];

    //This NSLog makes the app crash with an unrecognized selector sent error
    NSLog(@"User ID: %@",[jsonResponse objectForKey:@"uid"]);
}
         failure:^(AFHTTPRequestOperation *operation, NSError *error)
{
             NSLog(@"%@", [error localizedDescription]);
             [responseField setText:[error localizedDescription]];
}];

---

您缺少对

setDefaultHeader:value:

的调用，无法将

Accept

头设置为

application/json

。没有这个，JSON操作类就不会被使用，这意味着回到

AFHTTPRequestOperation

，它使用

responseData

作为其

responseObject

只需使用

setDefaultHeader:value:

将默认头Accept设置为

application/json

值，以便告诉AFHTTPRequestOperation我们在回调中得到的实际上是json。

您确实检查了

responseObject

？完整的错误消息会很有帮助…抱歉，添加了完整的错误消息。至于responseObject的类，我用isKindOfClass方法检查了一下，它实际上是一个NSData。从上面的注释来看，

self.jsonResponse

的第二个赋值，听起来你已经解决了这个问题。您需要使用

NSJSONSerialization

API将

NSData

转换为字典。正确！头球已经设置好，一切都很顺利，马特·汤普森！感谢您的图书馆，祝您在Heroku项目中好运。

{"uid":"98545931","token":"98545931:176:ec0b862ba57fef88394950dd0cc41491"}