golang 获取当前年月日周

func WeekByDate(t time.Time) (y int, m int, w int, d string) {
   yearDay := t.YearDay()
   yearFirstDay := t.AddDate(0, 0, -yearDay+1)
   firstDayInWeek := int(yearFirstDay.Weekday())
   //今年第一周有几天
   firstWeekDays := 1
   if firstDayInWeek != 0 {
      firstWeekDays = 7 - firstDayInWeek + 1
   }
   var week int
   if yearDay <= firstWeekDays {
      week = 1
   } else {
      if (yearDay-firstWeekDays)%7 > 0 {
         week = (yearDay-firstWeekDays)/7 + 2
      } else {
         week = (yearDay-firstWeekDays)/7 + 1
      }
   }

   m, _ = strconv.Atoi(t.Format("1"))
   day := t.Format(LayoutDate)
   //fmt.Println(t.Year(),m, week,day)
   return t.Year(), m, week, day
}