URL编码数据转换为JSON数据
NSString *urlString;
urlString=[self URLDecodedString:urlString];
-(NSString *)URLDecodedString:(NSString*)str
{
return (__bridge NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(kCFAllocatorDefault,
(CFStringRef)str,
CFSTR(""),
kCFStringEncodingUTF8);
}