使用AFNetworking遇到异常 Request failed: unacceptable content-type: text/html

把text/html这种json序列化(serializer)成二进制格式(NSData)，然后再解析出来，就是用NSData当中间层。

AFHTTPSessionManager *client = [[AFHTTPSessionManager alloc] init];
client.requestSerializer = [AFHTTPRequestSerializer serializer];
client.responseSerializer = [AFHTTPResponseSerializer serializer];

拿到responseObject后，如果外层是字典：

NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];