暂时蒙圈的我先上几个可用的code 但是具体区别 im not sure
第一段：Xcode自带 包含base64和gbk
NSStringEncoding gbkEncoding1 =CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);
NSString *result1 = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
NSData*decodedData = [[NSDataalloc]initWithBase64EncodedString:result1options:0];
NSString*jsonstring = [[NSStringalloc]initWithData:decodedDataencoding:gbkEncoding1];
NSData *jsondata = [jsonstring dataUsingEncoding:NSUTF8StringEncoding];
NSMutableDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsondata options:NSJSONReadingMutableContainers error:nil];
第二段：Xcode自带
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];
第三段：SBJson
NSString *responseString = [NSString stringWithString:[string stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
NSDictionary*request_Json = [stringJSONValue];
