用channel控制goroutine的退出

本文简要介绍了，如何用channel控制goroutine的退出的基本方法

for-range主动停止goruitine

package mainimport ("fmt""sync""time"
)/*
Go并发编程模型：主动停止goroutine
方法一：for-rang从channel上接收值，直到channel关闭
*/
var wg sync.WaitGroupfunc work(ch chan int) {defer wg.Done()// for range关键字，将其使用在channel上时，会自动等待channel的动作一直到channel被关闭close// 也就是clase(sh)后，for range就会退出for i := range ch {fmt.Println(i)}fmt.Println("work exit")
}func main() {wg.Add(1)var ch chan intch = make(chan int)go work(ch)for i := 0; i < 3; i++ {time.Sleep(1 * time.Second)ch <- i}time.Sleep(3 * time.Second)for i := 4; i < 7; i++ {time.Sleep(1 * time.Second)ch <- i}// close(sh)来控制"work"协程中的for range的完成close(ch)wg.Wait()
}

后台定时任务

	// 设定一个定时器，当定时器触发是就执行一次任务tricker := time.NewTicker(1 * time.Second)defer fmt.Println("tricker.Stop()")defer tricker.Stop()for {select {case <-stopCh:fmt.Println("do1 exit.")return//心跳，心跳一次就执行一次任务case <-tricker.C:time.Sleep(1 * time.Second)fmt.Println("do1 doing....")}}

使用stopCh控制goroutine退出

package mainimport ("fmt""sync""time"
)var wg sync.WaitGroupfunc do1(stopCh chan struct{}) {defer wg.Done()for {select {case <-stopCh:fmt.Println("go1 exit.")returndefault:time.Sleep(1 * time.Second)fmt.Println("go1 doing....")}}
}
func do2(stopCh chan struct{}) {defer wg.Done()for {select {case <-stopCh:fmt.Println("go2 exit.")returndefault:time.Sleep(1 * time.Second)fmt.Println("go2 doing....")}}
}func main() {wg.Add(2)stopCh := make(chan struct{})go do1(stopCh)go do2(stopCh)time.Sleep(5 * time.Second)// 让一个goroutine退出stopCh <- struct{}{}time.Sleep(5 * time.Second)// 让另一个goroutine退出stopCh <- struct{}{}wg.Wait()}

关闭channel来控制goroutine退出

package mainimport ("fmt""sync""time"
)/*
多个通道都关闭才退出
利用select的一个特性，select不会在nil的通道上进行等待
*/
var wg sync.WaitGroupfunc work(in, exit1, exit2 chan bool) {defer wg.Done()for {select {// 当exit管道收到信号后退出goroutinecase v := <-exit1:fmt.Println("exit1 收到退出信号")fmt.Println("v=", v)exit1 = nilcase <-exit2:fmt.Println("exit2 收到退出信号")exit2 = nilcase value := <-in:fmt.Println(value)}fmt.Println(time.Now())fmt.Println("遍历了一次")// 当2个退出通道都收到信号时，就退出for循环if exit1 == nil && exit2 == nil {return}}}func main() {in := make(chan bool)exit1 := make(chan bool)exit2 := make(chan bool)wg.Add(1)go work(in, exit1, exit2)for i := 0; i < 6; i++ {time.Sleep(5 * time.Millisecond)in <- true}// 主动停止goroutine方法一//exit1 <- 1//exit2 <- 1// 主动停止goroutine方法二close(exit1)close(exit2)wg.Wait()}