Go之time包用法

time包提供了時間的顯示和測量用的函式。日曆的計算採用的是公曆。
time 型別

type Time struct {
// wall and ext encode the wall time seconds, wall time nanoseconds,
// and optional monotonic clock reading in nanoseconds.
//
// From high to low bit position, wall encodes a 1-bit flag (hasMonotonic),
// a 33-bit seconds field, and a 30-bit wall time nanoseconds field.
// The nanoseconds field is in the range [0, 999999999].
// If the hasMonotonic bit is 0, then the 33-bit field must be zero
// and the full signed 64-bit wall seconds since Jan 1 year 1 is stored in ext.
// If the hasMonotonic bit is 1, then the 33-bit field holds a 33-bit
// unsigned wall seconds since Jan 1 year 1885, and ext holds a
// signed 64-bit monotonic clock reading, nanoseconds since process start.
wall uint64
ext  int64

    // loc specifies the Location that should be used to
    // determine the minute, hour, month, day, and year
    // that correspond to this Time.
    // The nil location means UTC.
    // All UTC times are represented with loc==nil, never loc==&utcLoc.
    loc *Location
}

time可以精確到納秒
示例

package main

import (
    "fmt"
    "time"
)

func main() {
    t:=time.Now()
    fmt.Println(t)//獲取當前時間2021-09-23 10:55:44.831571 +0800 CST m=+0.000090412
    fmt.Println(t.Unix())//獲取當前時間時間戳 1632366278
    fmt.Println(t.UnixMilli())//獲取當前時間毫秒 1632366278605
    fmt.Println(t.UnixMicro())//獲取當前時間微秒 1632366278605122
    fmt.Println(t.UnixNano())//獲取當前時間時納秒 1632366278605122000
    fmt.Println(t.Hour())//獲取當前小時 10
    fmt.Println(t.Day())//獲取當前天 23
    fmt.Println(t.Weekday())//獲取當前周Thursday
    fmt.Println(t.ISOWeek())//獲取當前周2021 38

    //格式化當前時間表示
    fmt.Println(t.String())//字元型
    fmt.Println(t.Format("2006-01-02 15:04:05"))//2021-09-23 11:12:42
    fmt.Println(t.Format("2006-01-02"))//2021-09-23
    fmt.Println(t.Format("15:04:05"))//11:12:42

    //指定時間戳轉換
    fmt.Println(time.Unix(1632366278, 0).Format("2006-01-02 15:04:05"))//2021-09-23 11:04:38
    //指定時間轉時間戳
    tm2, _ := time.Parse("2006-01-02 15:04:05", "2021-09-23 11:04:38")
    fmt.Println( tm2.Unix())//1632395078

    //"2021-09-08T08:18:46+08:00" 轉2021-09-08 08:18:46
    t, _= time.Parse(time.RFC3339, "2021-09-08T08:18:46+08:00")
    fmt.Println(t.Format("2006-01-02 15:04:05"))
    //2021-09-07T17:01:34.182659088Z 轉2021-09-07 17:01:34
    t, _= time.Parse(time.RFC3339Nano, "2021-09-07T17:01:34.182659088Z")
    fmt.Println(t.Format("2006-01-02 15:04:05"))
    //其他格式類似可參考

    //ANSIC       = "Mon Jan _2 15:04:05 2006"
    //UnixDate    = "Mon Jan _2 15:04:05 MST 2006"
    //RubyDate    = "Mon Jan 02 15:04:05 -0700 2006"
    //RFC822      = "02 Jan 06 15:04 MST"
    //RFC822Z     = "02 Jan 06 15:04 -0700" // 使用數字表示時區的RFC822
    //RFC850      = "Monday, 02-Jan-06 15:04:05 MST"
    //RFC1123     = "Mon, 02 Jan 2006 15:04:05 MST"
    //RFC1123Z    = "Mon, 02 Jan 2006 15:04:05 -0700" // 使用數字表示時區的RFC1123
    //RFC3339     = "2006-01-02T15:04:05Z07:00"
    //RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"
    //Kitchen     = "3:04PM"
    //// 方便的時間戳
    //Stamp      = "Jan _2 15:04:05"
    //StampMilli = "Jan _2 15:04:05.000"
    //StampMicro = "Jan _2 15:04:05.000000"
    //StampNano  = "Jan _2 15:04:05.000000000"

     //設定時區 Location
    //預設UTC
    loc, _ := time.LoadLocation("")
    // 伺服器設定的時區，一般為CST
    //loc, _ := time.LoadLocation("Local")
    //loc, _ := time.LoadLocation("Asia/Shanghai")
    t.In(loc).Format("2006-01-02 15:04:05");

    //1.5s後
    now := time.Now()
    tp, _ := time.ParseDuration("1.5s")
    fmt.Println(tp,tp.Truncate(1000), tp.Seconds(), tp.Nanoseconds())
    m1 := now.Add(tp)
    fmt.Println(m1)//2021-09-23 14:30:42.006213 +0800 CST m=+1.500352171

    //1個小時前
    tp, _ = time.ParseDuration("-1h")

    m1 = now.Add(tp)
    fmt.Println(m1)//2021-09-23 13:30:40.506213 +0800 CST m=-3599.999647829
    //休眠時間
    //time.Sleep(time.Duration(10) * time.Second)

    // func After(d Duration) <-chan Time  非阻塞,可用於延遲
    //time.After(time.Duration(10) * time.Second)



    // func Since(t Time) Duration 兩個時間點的間隔
    start := time.Now()
    fmt.Println(time.Since(start))   // 等價於 Now().Sub(t)， 可用來計算一段業務的消耗時間

    //func Until(t Time) Duration     //  等價於 t.Sub(Now())，t與當前時間的間隔


    time3 := "2021-03-20 08:50:29"
    time4 := "2021-03-20 08:50:29"
    //先把時間字串格式化成相同的時間型別
    t3, _ := time.Parse("2006-01-02 15:04:05", time3)
    t4, _ := time.Parse("2006-01-02 15:04:05", time4)

    fmt.Println(t3.Equal(t4)) //true


    now = time.Now()
    //Ticker 型別包含一個 channel，有時我們會遇到每隔一段時間執行的業務(比如設定心跳時間等)，就可以用它來處理，這是一個重複的過程

    // 無法取消
    //tick := time.Tick(1 * time.Minute)
    //for _ = range tick {
    //    // do something
    //}
    //NewTicker返回一個新的Ticker，該Ticker包含一個通道欄位，並會每隔時間段d就向該通道傳送當時的時間。它會調整時間間隔或者丟棄tick資訊以適應反應慢的接收者。如果d<=0會panic。關閉該Ticker可以釋放相關資源。
    // 可通過呼叫ticker.Stop取消
    //建立一個週期性的定時器
    //設定定時器為3秒
    timer := time.NewTimer(3 * time.Second)
    fmt.Println("當前時間為:", time.Now())

    t = <-timer.C //從定時器拿資料
    fmt.Println("當前時間為:", t)
    timer.Stop()//停止
    
}

links

https://studygolang.com/pkgdoc

Go之time包用法

Go之time包用法

links

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