go常用时间函数

// YesterdayDate 获取昨日
func YesterdayDate() string {
    now := time.Now()
    return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.Local).AddDate(0, 0, -1).Format("2006-01-02")
}

// WeekDate 获取本周第一天和本周最后一天
// weekType = 1 本周
// weekType = 2 上周
func WeekDate(weekType int) (weekStart string, weekEnd string) {
    var offset, offsetStart, offsetEnd int

    now := time.Now()
    //初始化获取本周一
    offset = int(time.Monday - now.Weekday())
    if offset > 0 {
        offset = -6
    }

    if weekType == 1 { //本周
        offsetStart = offset
    } else { //上周一
        offsetStart = offset - 7
    }

    offsetEnd = 6 + offsetStart - 7 //返回时间是6天
    weekStart = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.Local).AddDate(0, 0, offsetStart).Format("2006-01-02")
    weekEnd = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.Local).AddDate(0, 0, offsetEnd).Format("2006-01-02")
    return
}

// MonthDate 获取本月第一天和本月最后一天
// monthType = 1 本月
// monthType = 2 上月
func MonthDate(monthType int) (monthStart string, monthEnd string) {
    var offsetMonthStart int

    now := time.Now()
    if monthType == 1 {
        offsetMonthStart = 0
    } else {
        offsetMonthStart = -1
    }

    monthStart = time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, time.Local).AddDate(0, offsetMonthStart, 0).Format("2006-01-02")
    monthEnd = time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, time.Local).AddDate(0, offsetMonthStart+1, -1).Format("2006-01-02")
    return
}

// YearDate 获取本年第一天和本年最后一天
// yearType = 1 今年
// yearType = 2 去年
func YearDate(yearType int) (yearStart string, yearEnd string) {
    var offsetYearStart int

    now := time.Now()
    if yearType == 1 {
        offsetYearStart = 0
    } else {
        offsetYearStart = -1
    }

    yearStart = time.Date(now.Year(), 1, 1, 0, 0, 0, 0, time.Local).AddDate(offsetYearStart, 0, 0).Format("2006-01-02")
    yearEnd = time.Date(now.Year(), 1, 1, 0, 0, 0, 0, time.Local).AddDate(offsetYearStart+1, 0, -1).Format("2006-01-02")
    return
}