1 // 当前时间创建NSDate NSDate *myDate = [NSDate date]; NSLog(@"myDate = %@",myDate); 2 //从现在开始的24小时 NSTimeInterval secondsPerDay = 24*60*60; NSDate *tomorrow = [NSDate dateWithTimeIntervalSinceNow:secondsPerDay]; NSLog(@"myDate = %@",tomorrow); 3//根据已有日期创建日期 NSTimeInterval secondsPerDay1 = 24*60*60; NSDate *now = [NSDate date]; NSDate *yesterDay = [now addTimeInterval:-secondsPerDay1]; NSLog(@"yesterDay = %@",yesterDay); 4//比较日期 BOOL sameDate = [now isEqualToDate:yesterDay]; NSLog(@"sameDate = %lu",sameDate); 4.1//获取较早的日期 NSDate *earlierDate = [yesterDay earlierDate:now]; NSLog(@"earlierDate = %@",earlierDate); 4.2//较晚的日期 NSDate *laterDate = [yesterDay laterDate:now]; NSLog(@"laterDate = %@",laterDate); //两个日期之间相隔多少秒 NSTimeInterval secondsBetweenDates= [yesterDay timeIntervalSinceDate:now]; NSLog(@"secondsBetweenDates= %lf",secondsBetweenDates); //通过NSCALENDAR类来创建日期 NSDateComponents *comp = [[NSDateComponentsalloc]init]; [comp setMonth:06]; [comp setDay:01]; [comp setYear:2001]; NSCalendar *myCal = [[NSCalendaralloc]initWithCalendarIdentifier:NSGregorianCalendar]; NSDate *myDate1 = [myCal dateFromComponents:comp]; NSLog(@"myDate1 = %@",myDate1); //从已有日期获取日期 unsigned units = NSMonthCalendarUnit|NSDayCalendarUnit|NSYearCalendarUnit; NSDateComponents *comp1 = [myCal components:units fromDate:now]; NSInteger month = [comp1 month]; NSInteger year = [comp1 year]; NSInteger day = [comp1 day]; //NSDateFormatter实现日期的输出 NSDateFormatter *formatter = [[NSDateFormatteralloc]init]; [formatter setDateStyle: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 = [formatter stringFromDate:now]; NSLog(@"string = %@",string); NSLog(@"formater = %@",formatter); //获取日期格式对象 - (NSDateFormatter *)dateFormatter { if (dateFormatter == nil) { dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateStyle:NSDateFormatterMediumStyle]; [dateFormatter setTimeStyle:NSDateFormatterNoStyle]; } return dateFormatter; }