从NSDate获取年月日时分秒

 

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

	NSInteger unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekdayCalendarUnit |
	NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
	
	NSDateComponents *comps  = [calendar components:unitFlags fromDate:date];
	
	int year = [comps year];
	int month = [comps month];
	int day = [comps day];
	int hour = [comps hour];
	int min = [comps minute];
        int sec = [comps second];

这样获取的hour都是24小时制的, 不管手机实际日期是否是用24小时显示.