Str转Json

NSString *str =  @"{'extype':1,'name':'jiadan','pwd':'6e03a39847c297813d3d80a1935efd89','serverid':10024,'ip':'121.42.162.93'}";
str = [str stringByReplacingOccurrencesOfString:@"'" withString:@"\""];

NSData * data = [str dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
NSLog(@"%@",[self DataTOjsonString:str]);

字符串格式化转为json