：<NSHTTPURLResponse: 0x17003a900> { URL: 你的url地址 } { status code: 500, 

headers {
 "Cache-Control" = private
 "Content-Length" = 3306;
 "Content-Type" = "text/html; charset=utf-8";
 Date = "Sun, 09 Oct 2016 07:45:13 GMT";
 Server = "Microsoft-IIS/7.5";
 "X-AspNet-Version" = "4.0.30319";
 "X-Powered-By" = "ASP.NET";
} }

[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; 

[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"]; 

<NSHTTPURLResponse: 0x17403fe60> { URL: 你的url地址 } { status code: 200, headers {
 "Cache-Control" = private;
 "Content-Length" = 75;
 "Content-Type" = "application/json; charset=utf-8";
 Date = "Sun, 09 Oct 2016 07:56:16 GMT";
 Server = "Microsoft-IIS/7.5";
 "X-AspNet-Version" = "4.0.30319";
 "X-AspNetMvc-Version" = "4.0";
 "X-Powered-By" = "ASP.NET";
} }