Golang time

package main

import (
    "time"
    "fmt"
)
func main() {
    fmt.Println(time.Now().Unix() - 7*24*60*60)
    t1 := time.Now()
    t2 := t1.Add(time.Hour)
    t3 := time.Unix(1487780010, 0)
    //分别指定年，月，日，时，分，秒，纳秒，时区
    ft := time.Date(2018, time.Month(1), 11, 5, 13, 32, 0, t1.Location())
    fmt.Println(ft)
    fmt.Println(t1, t2, t3)

    p := t1.Format("2006-01-02 15:04:05")
    fmt.Println(p)
    t3 := time.Unix(1487780010, 0)
    fmt.Println(t1, t2, t3)
    if t3.After(t1) {
        fmt.Println("t3 is after t1")
    } else {
        fmt.Println("t3 is before t1")
    }
    fmt.Println(time.Since(t3))
}

输出结果：

1515662587
2018-01-11 05:13:32 +0800 CST
2018-01-18 17:23:07.614331553 +0800 CST m=+0.000305934 2018-01-18 18:23:07.614331553 +0800 CST m=+3600.000305934 2017-02-23 00:13:30 +0800 CST

2018-01-18 17:38:35
t3 is before t1
8026h46m15.524359287s

time.After超时应用

package main

import (
    "fmt"
    "time"
)

func main() {
    c := make(chan bool)
    select {
    case v:= <-c:
        fmt.Println(v)
    case <-time.After(3 * time.Second):
        fmt.Println("Timeout")
    }
}

注意：使用time Format的时，最好使用常量类型的类型。比如

const (
    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" // RFC822 with numeric zone
    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" // RFC1123 with numeric zone
    RFC3339     = "2006-01-02T15:04:05Z07:00"
    RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"
    Kitchen     = "3:04PM"
    // Handy time stamps.
    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"
)

上述都是 time包中的常量。在format 时间格式时最好使用他们，否则可能出现时间的变动。

package main


import (
    "fmt"
    "time"
)

func main() {
    t1 := time.Now()
    t2 := t1.Format(time.Kitchen)
    fmt.Println(t2)
}

Output:

9:47AM

Since

func Since(t Time) Duration {
    return Now().Sub(t)
}

返回从t时刻已经过去多久

Until

func Until(t Time) Duration {
    return t.Sub(Now())
}

返回持续了多久，直到t.

t1 := time.Now()
t3 := time.Unix(t1.Unix()-7*24*60*60, 0)
fmt.Println(time.Until(t3).Seconds())

示例中，因为传入的参数是过去的一个时间点，所以，结果是负值。

Hours

func (d Duration) Hours() float64 {
    hour := d / Hour
    nsec := d % Hour
    return float64(hour) + float64(nsec)/(60*60*1e9)
}

t4,_ := time.ParseDuration("4h30m")
fmt.Printf("%v\n",t4.Hours())

Output:

4.5

Minutes

func (d Duration) Minutes() float64 {
    min := d / Minute
    nsec := d % Minute
    return float64(min) + float64(nsec)/(60*1e9)
}

t4,_ := time.ParseDuration("4h30m")
fmt.Printf("%v\n",t4.Minutes())

Output:

270

Nanoseconds纳秒

func (d Duration) Nanoseconds() int64 {
        return int64(d) 
}

ns, _ := time.ParseDuration("1000ns")
fmt.Printf("one microsecond has %d nanoseconds.", ns.Nanoseconds())

Output:

one microsecond has 1000 nanoseconds.

NewTicker

    ticker := time.NewTicker(time.Second)
    defer ticker.Stop()
    done := make(chan bool)
    go func() {
        time.Sleep(10 * time.Second)
        done <- true
    }()
    for {
        select {
        case <-done:
            fmt.Println("Done!")
            return
        case t := <-ticker.C:
            fmt.Println("Current time: ", t)
        }
    }

Output:

Current time:  2018-02-05 10:41:37.204211269 +0800 CST m=+1.001535613
Current time:  2018-02-05 10:41:38.204068714 +0800 CST m=+2.001320058
Current time:  2018-02-05 10:41:39.204252518 +0800 CST m=+3.001503862
Current time:  2018-02-05 10:41:40.204103403 +0800 CST m=+4.001281747
Current time:  2018-02-05 10:41:41.204360898 +0800 CST m=+5.001539242
Current time:  2018-02-05 10:41:42.204120805 +0800 CST m=+6.001227149
Current time:  2018-02-05 10:41:43.204406187 +0800 CST m=+7.001439531
Current time:  2018-02-05 10:41:44.203708482 +0800 CST m=+8.000741826
Current time:  2018-02-05 10:41:45.204431933 +0800 CST m=+9.001392277
Current time:  2018-02-05 10:41:46.204367246 +0800 CST m=+10.001327590
Done!