golang的time使用

package main

import (
	"time"
	"fmt"
)

func main() {

	a := time.Now().Unix()
	fmt.Println("时间戳---", a)

	// 2006-01-02 15:04:05 记住这一刻
	b := time.Now().Format("2006-01-02 15:04:05")
	fmt.Println("格式化时间", b)

	/**
	func (t Time) Add(d Duration) Time
	Duration如下
	const (
		Nanosecond  Duration = 1
		Microsecond          = 1000 * Nanosecond
		Millisecond          = 1000 * Microsecond
		Second               = 1000 * Millisecond
		Minute               = 60 * Second
		Hour                 = 60 * Minute
	)
	 */
	c := time.Now().Add(time.Minute * 3)
	fmt.Println("3分钟后时间", c.Format("2006-01-02 15:04:05"))

	/**
		func (t Time) AddDate(years int, months int, days int) Time
	*/
	d := time.Now().AddDate(-1, 1,10)
	fmt.Println("时间", d.Format("2006-01-02 15:04:05"))

	// 返回年月日三个值
	fmt.Println(time.Now().Date())
	// 返回时分秒三个值
	fmt.Println(time.Now().Clock())


	fmt.Println(time.Now().Year(), time.Now().Month(), time.Now().Day())
	fmt.Println(time.Now().Weekday(), time.Now().Hour())
	fmt.Println(time.Now().YearDay())

	fmt.Println(time.Since(d))


	// tring返回采用如下格式字符串的格式化时间。
	// "2006-01-02 15:04:05.999999999 -0700 MST"
	fmt.Println(time.Now().String())

	time.AfterFunc(2*time.Second, func() {
		fmt.Println("hello 2s")
	})

	loc, _ := time.LoadLocation("Asia/Shanghai")
	const longForm = "Jan 2, 2006 at 3:04pm (MST)"
	const shortForm = "2006-Jan-02"
	t, _ := time.ParseInLocation(longForm, "Jul 9, 2012 at 5:02am (CEST)", loc)
	fmt.Println(t)
	
	/**
	func ParseInLocation(layout, value string, loc *Location) (Time, error)
	 */
	t, _ = time.ParseInLocation(shortForm, "2022-Jul-09", loc)
	fmt.Println(t)

	/**
	func Parse(layout, value string) (Time, error)

	解析一个格式化的时间字符串并返回它代表的时间
	ParseInLocation类似Parse但有两个重要的不同之处。
	第一，当缺少时区信息时，Parse将时间解释为UTC时间，而ParseInLocation将返回值的Location设置为loc；
	第二，当时间字符串提供了时区偏移量信息时，Parse会尝试去匹配本地时区，而ParseInLocation会去匹配loc
	*/
	t, _ = time.Parse(longForm, "Feb 3, 2023 at 7:54pm (PST)")
	fmt.Println(t)
	
	
	t, _ = time.Parse(shortForm, "2020-Feb-03")
	fmt.Println(t)

	ch := make(chan int)
	timeout := time.After(time.Second * 2)
	timer := time.NewTimer(time.Second * 4) 
	var i int
	go func() {
		for {
			// i++
			select {
				case <- ch:
					fmt.Println("channel close")
					return
				case <- timer.C:
					fmt.Println("4s的NewTimer定时任务")
				case <- timeout:
					fmt.Println("4s定时输出")
				case <- time.After(time.Second * 6):
					fmt.Println("6s到了") 
				// default:
				// 	//Sleep 1秒，参数就是上面的Duration
				// 	time.Sleep(time.Second * 1)
				// 	fmt.Println("go 1s")
			}
		}
	}()
	time.Sleep(time.Second * 15)
	fmt.Println("close----")
	close(ch)
	time.Sleep(time.Second * 2)
}