[obj-c] 날짜 형식 변환, NSDateFormatter

날짜 형식을 다른 형식으로 바꾸기. 

1999-10-12 11:10:22.111   ->  99.10.12 11:10

NSString *dateString = @"1999-10-12 11:10:22.111";

      NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];

        [dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];

        [dateFormat setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

        NSDate *date = [dateFormat dateFromString:dateString];

        [dateFormat setDateFormat:@"yy/MM/dd HH:mm"];

        NSString *stringFromDate = [dateFormat stringFromDate:date];