package main
import (
"context"
"fmt"
"golang.org/x/sync/semaphore"
"sync"
)
func doSomething(u string) { // 模拟抓取任务的执行
//time.Sleep(2 * time.Second)
fmt.Println(u)
}
const (
Limit = 2 // 同時并行运行的goroutine上限
Weight = 1 // 每个goroutine获取信号量资源的权重
)
var TeshChannel = make(chan int, 1000) // 定义一个带缓冲的channel
func traversalArr(datas []string) {
s := semaphore.NewWeighted(Limit)
var w sync.WaitGroup
for _, u := range datas {
w.Add(1)
go func(u string) {
err := s.Acquire(context.Background(), Weight)
if err != nil {
fmt.Println(err)
}
doSomething(u)
s.Release(Weight)
w.Done()
}(u)
}
w.Wait()
}
func traversalChannel() {
s := semaphore.NewWeighted(Limit)
var w sync.WaitGroup
for u := range TeshChannel {
w.Add(1)
go func(u int) {
//fmt.Println("traversal num: ", u)
err := s.Acquire(context.Background(), Weight)
if err != nil {
fmt.Println(err)
}
//doSomething(strconv.Itoa(u))
doSomething(fmt.Sprintf("this is %d", u))
s.Release(Weight)
w.Done()
}(u)
}
w.Wait()
}
func main() {
// arr test
urls := []string{
"http://www.example.com",
"http://www.example.net",
"http://www.example.net/foo",
"http://www.example.net/bar",
"http://www.example.net/baz",
}
traversalArr(urls)
fmt.Println("Arr Test Done")
// channel test
for i := 1; i <= 10; i++ {
fmt.Println("input chan: ", i)
TeshChannel <- i
}
close(TeshChannel)
traversalChannel() // TODO 疑问,调用该方法,打印出来的是无序的?
fmt.Println("Channel Test Done")
fmt.Println("All Done")
}
golang — Управление параллелизмом через массивы и каналы через семафоры
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Origin blog.csdn.net/xuezhangjun0121/article/details/132714234
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