Go语言笔记

Select

Select

Go里面的Select和Java Nio里面的模式有点类似，就是一个线程(进程/协程)同时去监听多个目标的状态。在Go里面，Select可以让一个Goroutine同时去监听多个Channel是否到达准备状态，例子如下：

	timeOut := make(chan bool, 1)
	go func() {
		time.Sleep(time.Duration(time.Second * 5))
		timeOut <- true
	}()
	timeOutNext := make(chan bool, 1)
	go func() {
		time.Sleep(time.Duration(time.Second * 10))
		timeOutNext <- true
	}()
	select {
	case <-timeOut:
		fmt.Println("TimeOut After 5 Seconds!")
	case <-timeOutNext:
		fmt.Println("TimeOut After 10 Seconds!")
	}

上面代码执行时，Select阻塞到timeOut这个Channel收到输入时就退出了，要让Select不退出，timeOutNext这个Channel也有机会收到输入时，需要像下面这样写：

	timeOut := make(chan bool, 1)
	go func() {
		time.Sleep(time.Duration(time.Second * 5))
		timeOut <- true
	}()
	timeOutNext := make(chan bool, 1)
	go func() {
		time.Sleep(time.Duration(time.Second * 10))
		timeOutNext <- true
	}()
	for {
		select {
		case <-timeOut:
			fmt.Println("TimeOut After 5 Seconds!")
		case <-timeOutNext:
			fmt.Println("TimeOut After 10 Seconds!")
		}
	}