iphone - NSDateFormatter +dateFormatFromTemplate :options:locale: BUG?

Question

请参阅下面的代码和输出。

 NSDateComponents *dateComponents = [[[NSDateComponents alloc] init] autorelease];
 [dateComponents setYear:2011];
 [dateComponents setMonth:1];
 [dateComponents setDay:1];

 NSDate *date = [[NSCalendar currentCalendar] dateFromComponents:dateComponents];

 NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
 [dateFormatter setDateFormat:[NSDateFormatter dateFormatFromTemplate:@"YYYYMMMd" options:0 locale:[NSLocale currentLocale]]];

 NSString *dateString = [dateFormatter stringFromDate:date];

 NSLog(@"Happy New Year: %@", dateString);

您期望输出什么？

 Happy New Year: Jan 1, 2011

但是结果是......

 Happy New Year: Jan 1, 2010

怎么了？请帮忙...

Answer 1

模板格式字符串应为@"yyyyMMMd"(小写“y”代表年份)。

大写的“Y”是别的东西(参见Unicode Date Format Patterns)。