go get github.com/robfig/cron/v3@v3.0.0

import "github.com/robfig/cron/v3"

package main

import (
	"fmt"
	"github.com/robfig/cron/v3"
)

func main() {
	// 創(chuàng)建一個(gè)默認(rèn)的cron對(duì)象
    c := cron.New()
    
    //添加執(zhí)行任務(wù)
	c.AddFunc("30 * * * *", func() { fmt.Println("Every hour on the half hour") })
	c.AddFunc("@hourly", func() { fmt.Println("Every hour, starting an hour from now") })
	c.AddFunc("@every 1h30m", func() { fmt.Println("Every hour thirty, starting an hour thirty from now") })
	
    //開始執(zhí)行任務(wù)
    c.Start()
	select {} //阻塞
}

Field name   | Mandatory? | Allowed values  | Allowed special characters
----------   | ---------- | --------------  | --------------------------
Seconds      | Yes        | 0-59            | * / , -
Minutes      | Yes        | 0-59            | * / , -
Hours        | Yes        | 0-23            | * / , -
Day of month | Yes        | 1-31            | * / , - ?
Month        | Yes        | 1-12 or JAN-DEC | * / , -
Day of week  | Yes        | 0-6 or SUN-SAT  | * / , - ?

// 創(chuàng)建一個(gè)默認(rèn)的cron對(duì)象
cron.New()

// 自定義解析器
cron.New(cron.WithSeconds())

// Seconds field, optional
cron.New(cron.WithParser(cron.NewParser(
    cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor,
)))

// 有兩個(gè)參數(shù)，第一個(gè)參數(shù)可以是cron表達(dá)式或者預(yù)定義時(shí)間表，第二個(gè)Job
func (c *Cron) AddJob(spec string, cmd Job) (EntryID, error)

// Job是一個(gè)接口，有一個(gè)Run方法
type Job interface {
	Run()
}

// 有兩個(gè)參數(shù)，第一個(gè)參數(shù)可以是cron表達(dá)式或者預(yù)定義時(shí)間表，第二個(gè)傳入一個(gè)函數(shù)，就是要執(zhí)行的任務(wù)
// 會(huì)返回一個(gè)Id和error
// 會(huì)把傳入的cmd func轉(zhuǎn)成FuncJob。FuncJob實(shí)現(xiàn)了Job接口
func (c *Cron) AddFunc(spec string, cmd func()) (EntryID, error) {
	return c.AddJob(spec, FuncJob(cmd))
}

go get github.com/gorhill/cronexpr //下載
import "github.com/gorhill/cronexpr" //導(dǎo)入

package main

import (
	"fmt"
	"time"

	"github.com/gorhill/cronexpr"
)

func doTask() {
	fmt.Println("I am running, time is: ", time.Now())
}
func main() {

	// 每隔 5 秒執(zhí)行1次
	expr, err := cronexpr.Parse("*/10 * * * * * * ") // 如果表達(dá)式解析錯(cuò)誤將返回一個(gè)錯(cuò)誤
	if err != nil {
		fmt.Println(err)
		return
	}
    
    //獲取下次執(zhí)行時(shí)間
	nextTime := expr.Next(time.Now()) 
	fmt.Println(nextTime)

	time.AfterFunc(time.Until(nextTime), doTask)
    
    //返回當(dāng)前crontab后的5次執(zhí)行,n為次數(shù)
    nextTimeList = cronexpr.MustParse("*/10 * * * * * * ").NextN(time.Now(), 5)
    for _, v := range nextTimeList {
        fmt.Println(v.String())
    } 
    
	time.Sleep(10 * time.Second)

}