iOS：json格式字符串转字典，字典转json格式字符串

//NSError *parseError = nil;

NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&parseError];

NSString *jsonStr=[[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

//json转换成字典就不用说了吧