go 定时器

川长思鸟来 2022-05-24 08:11 134阅读 0赞

## 有问题用法 ##

package main
    
    import (
        "encoding/json"
        "fmt"
        "sync/atomic"
        "time"
    )
    
    func demo() {
        for {
            select {
            case <-time.After(time.Second * 1):
                println("1s timer")
    
            case <-time.After(time.Second * 2):
                println("2s timer")
            }
        }
    }
    
    func main() {
    
        go demo()
        select {}
    }

![这里写图片描述][70]

看到2s的定时器一直没有执行，原因就是 select 每次执行都会重新执行 case 条件语句，并重新注册到 select ,每次都会新构造一个 Timer 对象，所以2秒的定时器永远不会执行。而且会造成内存的泄露。这样的设计倒是也有好处，定时器可用于另一个chan的超时处理

## 正确用法 ##

### code ###

func demo(t1 interface{}, t2 interface{}) {
        for {
            select { case <-t1.(*time.Ticker).C: println("1s timer") case <-t2.(*time.Ticker).C: println("2s timer") } } } func main() { t1 := time.NewTicker(time.Second * 1) t2 := time.NewTicker(time.Second * 2) go demo(t1, t2) select {} }

![这里写图片描述][70 1]

可以看到两个定时器都可以正常运行

## 引用 ##

> [https://blog.csdn.net/x356982611/article/details/80425030][https_blog.csdn.net_x356982611_article_details_80425030]  
> [https://blog.csdn.net/wl2002200/article/details/54565211][https_blog.csdn.net_wl2002200_article_details_54565211]  
> [https://godoc.org/time\#After][https_godoc.org_time_After]

[70]: /images/20220524/bd4142c1bdd148d58ae268cb063f931b.png
[70 1]: /images/20220524/530ab0d5803d4726941ed45c6f7e479d.png
[https_blog.csdn.net_x356982611_article_details_80425030]: https://blog.csdn.net/x356982611/article/details/80425030
[https_blog.csdn.net_wl2002200_article_details_54565211]: https://blog.csdn.net/wl2002200/article/details/54565211
[https_godoc.org_time_After]: https://godoc.org/time#After