不限制的时候，有多少业务开多少协程
func job(index int) {
time.Sleep(time.Millisecond * 500)
fmt.Println(index)
}
func main() {
wg := sync.WaitGroup{}
for i := 0; i < 100; i++ {
wg.Add(1)
go func(index int) {
defer wg.Done()
job(index)
}(i)
}
wg.Wait()
}
限制协程
var pool chan struct{}
func job(index int) {
time.Sleep(time.Millisecond * 500)
fmt.Println(index)
}
func main() {
wg := sync.WaitGroup{}
pool = make(chan struct{}, 10)
for i := 0; i < 100; i++ {
wg.Add(1)
pool <- struct{}{}
go func(index int) {
defer wg.Done()
defer func() {
<-pool
}()
job(index)
}(i)
}
wg.Wait()
}
或者
var pool chan struct{}
func job(index int, pool <-chan struct{}) {
defer func() {
<-pool
}()
time.Sleep(time.Millisecond * 500)
fmt.Println(index)
}
func main() {
wg := sync.WaitGroup{}
pool = make(chan struct{}, 10)
for i := 0; i < 100; i++ {
wg.Add(1)
pool <- struct{}{}
go func(index int) {
defer wg.Done()
job(index, pool)
}(i)
}
wg.Wait()
}
结果就变成分批打印了,达到限制的效果
