获取时间

NSDate *date = [NSDate date];

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *comps;

// 年月日获得

comps = [calendar components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit)

fromDate:date];

//    NSInteger year = [comps year];

//    NSInteger month = [comps month];

//    NSInteger day = [comps day];

//    NSLog(@"year: %d month: %d, day: %d", year, month, day);

//当前的时分秒获得

//    comps = [calendar components:(NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit)

//                        fromDate:date];

//    NSInteger hour = [comps hour];

//    NSInteger minute = [comps minute];

//    NSInteger second = [comps second];

//    NSLog(@"hour: %d minute: %d second: %d", hour, minute, second);

comps = [calendar components:(NSWeekCalendarUnit | NSWeekdayCalendarUnit | NSWeekdayOrdinalCalendarUnit)

fromDate:date];

//    NSInteger week = [comps week]; // 今年的第几周

NSInteger weekday = [comps weekday]; // 星期几（注意，周日是“1”，周一是“2”。。。。）

//    NSInteger weekdayOrdinal = [comps weekdayOrdinal]; // 这个月的第几周