Golang协程间的通信

通道（channel）是Golang中协程之间通信的重要方式

协程

• Golang中的协程和其它语言中定义的协程不太一样，Golang中的协程更倾向于并行；

协程之间的通信

	package main
	import (
		"fmt"
		"time"
	)

	func channelWrite(ch chan int){
		ch<-5//写入数据
		fmt.Println("I've  written it.")//写入以后阻塞，直到被读出以后才能执行打印语句
	}
	func channelRead(ch chan int){
		time.Sleep(3*1e9)
		fmt.Println("Read from a channel",<-ch)//读取数据以后才能解除阻塞
	}
	func main(){
		ch:=make(chan int)
		go channelWrite(ch)
		go channelRead(ch)
		time.Sleep(5*1e9)
	}

	package main
	import (
		"fmt"
		"time"
	)

	func channelWrite(ch chan int){
		ch<-5//写入数据
		fmt.Println("I've  written it.")//缓冲区未满，因此直接执行打印语句
	}
	func channelRead(ch chan int){
		time.Sleep(3*1e9)
		fmt.Println("Read from a channel",<-ch)//缓冲区未满，无法阻塞
	}
	func main(){
		ch:=make(chan in,5)//指定缓冲size=5
		go channelWrite(ch)
		go channelRead(ch)
		time.Sleep(5*1e9)
	}

协程的关闭：

	if v,ok:=<-ch;ok{
	...
	}

协程的切换/选择：

	func writeChan1(ch1 chan int){
		for i:=0;i<100;i++ {
			ch1 <-i
		}
	}
	func writeChan2(ch2 chan int){
		for i:=0;i<100;i++ {
			ch2 <-i
		}
	}
	func selectFunc(ch1,ch2 chan int){
		for{
		select{
		case val:=<-ch1:
				fmt.Printf("Got %v from channel 1\n",val)
		case val:=<-ch2:
				fmt.Printf("Got %v from channel 2\n",val)
		}
	}

	}
	func main(){
		ch1:=make(chan int)
		ch2:=make(chan int)
		defer close(ch1)
		defer close(ch2)
		go writeChan1(ch1)
		go writeChan2(ch2)
		go selectFunc(ch1,ch2)
		time.Sleep(1e9)
	}