IOS NSDate日期操作

1//当前时间创建NSDate

NSDate*myDate = [NSDatedate];

NSLog(@"myDate

= %@",myDate);

2//从现在开始的24小时

NSTimeIntervalsecondsPerDay =24*60*60;

NSDate*tomorrow = [NSDatedateWithTimeIntervalSinceNow:secondsPerDay];

NSLog(@"myDate

= %@",tomorrow);

3//根据已有日期创建日期

NSTimeIntervalsecondsPerDay1 =24*60*60;

NSDate*now = [NSDatedate];

NSDate*yesterDay = [nowaddTimeInterval:-secondsPerDay1];

NSLog(@"yesterDay

= %@",yesterDay);

4//比较日期

BOOLsameDate = [nowisEqualToDate:yesterDay];

NSLog(@"sameDate

= %lu",sameDate);

4.1//获取较早的日期

NSDate*earlierDate = [yesterDayearlierDate:now];

NSLog(@"earlierDate

= %@",earlierDate);

4.2//较晚的日期

NSDate*laterDate = [yesterDaylaterDate:now];

NSLog(@"laterDate

= %@",laterDate);

//两个日期之间相隔多少秒

NSTimeIntervalsecondsBetweenDates= [yesterDaytimeIntervalSinceDate:now];

NSLog(@"secondsBetweenDates=

%lf",secondsBetweenDates);

//通过NSCALENDAR类来创建日期

NSDateComponents*comp

= [[NSDateComponentsalloc]init];

[compsetMonth:06];

[compsetDay:01];

[compsetYear:2001];

NSCalendar*myCal

= [[NSCalendaralloc]initWithCalendarIdentifier:NSGregorianCalendar];

NSDate*myDate1 = [myCaldateFromComponents:comp];

NSLog(@"myDate1

= %@",myDate1);

//从已有日期获取日期

unsignedunits

=NSMonthCalendarUnit|NSDayCalendarUnit|NSYearCalendarUnit;

NSDateComponents*comp1 = [myCalcomponents:unitsfromDate:now];

NSIntegermonth = [comp1month];

NSIntegeryear = [comp1year];

NSIntegerday = [comp1day];

//NSDateFormatter实现日期的输出

NSDateFormatter*formatter

= [[NSDateFormatteralloc]init];

[formattersetDateStyle:NSDateFormatterFullStyle];//直接输出的话是机器码

//或者是手动设置样式[formatter setDateFormat:@"yyyy-mm-dd"];

NSString*string = [formatterstringFromDate:now];

NSLog(@"string

= %@",string);

NSLog(@"formater

= %@",formatter);

//获取日期格式对象

- (NSDateFormatter*)dateFormatter {

if(dateFormatter==nil) {

dateFormatter= [[NSDateFormatteralloc]init];

[dateFormattersetDateStyle:NSDateFormatterMediumStyle];

[dateFormattersetTimeStyle:NSDateFormatterNoStyle];

}

returndateFormatter;

}