go channel 理解

1、未使用go channel

package?main

import?(
????"fmt"
????"time"
)

func?printer(s?string)?{
????for?_,?v?:=?range?s?{
????????fmt.Println(string(v))
????????time.Sleep(time.Millisecond?*?3000)
????}
}

func?person()?{
????printer("hello")
}

func?person2()?{
????printer("world")
}
func?main()?{
????go?person()
????go?person2()
????for?{
????}
}

d:\goprojects\src\day1\練習>go?run?main.go
h
w
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exit?status?2

2、使用channel

package?main

import?(
????"fmt"
????"time"
)

var?ch?=?make(chan?int,?1)

func?printer(s?string)?{
????for?_,?v?:=?range?s?{
????????fmt.Println(string(v))
????????time.Sleep(time.Millisecond?*?3000)
????}
}

func?person()?{
????printer("hello")
????ch?<-?1
}

func?person2()?{
????<-ch

????printer("world")
}
func?main()?{
????go?person()
????go?person2()
????for?{
????}
}

d:\goprojects\src\day1\練習>go?run?main.go
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l
l
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d

3、小結

channel?有兩端，一端寫入（數據傳入）ch<-?;一端讀出（傳出數據）;要求讀寫兩端必須同時滿足條件，才能在channel上完成數據流動，否則阻塞。

4、 關閉channel

package?main

import?"fmt"

func?main()?{
????ch?:=?make(chan?int)
????go?func()?{
????????for?i?:=?0;?i?<?8;?i++?{
????????????ch?<-?i
????????}
????????close(ch)
????}()

????for?{
????????if?num,?ok?:=?<-ch;?ok?{
????????????fmt.Println(num)
????????}?else?{
????????????fmt.Println("channel?close")
????????????break

????????}
????}
}

d:\goprojects\src\day1\并發\exp1>go?run?main.go
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channel?close

d:\goprojects\src\day1\并發\exp1>