我有以下代码实现了工作队列：

package main

import (
    "fmt"
    "net/http"
    "io"
    "time"
)

var (
    linkQueue chan Link
    scraperQueue chan chan Link
)

func CycleDirectory(page int) {
    linkQueue <- Link{Name: "asd"}
}

type Link struct {
    Name string
}

func (s Scraper) Start() {
    fmt.Println("Started")
    go func() {
        for {
            s.ScraperQueue <- s.Link
            select {
            case link := <-s.Link:
                fmt.Println(fmt.Sprintf("%v", s.Id) + ": Received " + link.Name)
            case <-s.QuitChan:
                fmt.Println("Closed")
                return
            }
        }
    }()
}

func (s Scraper) Stop() {
    go func() {
        s.QuitChan <- true
    }()
}

type Scraper struct {
    Id int
    Link chan Link
    ScraperQueue chan chan Link
    QuitChan chan bool
}

func InitScraper(id int, scraperQueue chan chan Link) Scraper {
    return Scraper {
        Id: id,
        Link: make(chan Link),
        ScraperQueue: scraperQueue,
        QuitChan: make(chan bool),
    }
}

func HelloServer(w http.ResponseWriter, req *http.Request) {
    io.WriteString(w, "hello, world!\n")
}

func main() {
    linkQueue = make(chan Link, 2000)

    numScrapers := 2

    scraperQueue = make(chan chan Link, numScrapers)

    for i := 0; i < numScrapers; i++ {
        s := InitScraper(i+1, scraperQueue)
        s.Start()
    }

    go func() {
        for {
            select {
            case link := <-linkQueue:
                go func() {
                    scraper := <-scraperQueue
                    scraper <- link
                }()
            }
        }
    }()

    CycleDirectory(1)

    // time.Sleep(1 * time.Millisecond)

    for {
        // select {
        // }
    }

    // http.HandleFunc("/hello", HelloServer)

    // http.ListenAndServe(":12345", nil)
}

使用包含if语句（或内部没有任何内容）的for循环运行此代码，爬虫不会打印收到的消息。使用net /
http中的ListenAndServe函数进行阻止，它将打印收到的消息。使用睡眠阻止1毫秒，我收到了消息。并将select语句放入for循环中，我也收到消息。

为什么没有select语句的for循环不允许执行在工作队列中发送的消息，以及我将如何处理这一问题。我需要在for循环中使用if语句来检查是否所有工作都已完成，因此我可以退出循环并结束程序。

更新资料

Amd的建议是解决此问题的方法。这是我使用sync.WaitGroup包主要的更新代码

import (
    "fmt"
    "sync"
)

var (
    linkQueue chan Link
    scraperQueue chan chan Link
    wg sync.WaitGroup
)

func CycleDirectory(page int) {
    wg.Add(1)
    linkQueue <- Link{Name: "asd"}
}

type Link struct {
    Name string
}

func (s Scraper) Start() {
    fmt.Println("Started")
    go func() {
        for {
            s.ScraperQueue <- s.Link
            select {
            case link := <-s.Link:
                Scrape(s.Id, link.Name)
                s.Stop()
            case <-s.QuitChan:
                fmt.Println("Closed")
                wg.Done()
                return
            }
        }
    }()
}

func (s Scraper) Stop() {
    go func() {
        s.QuitChan <- true
    }()
}

type Scraper struct {
    Id int
    Link chan Link
    ScraperQueue chan chan Link
    QuitChan chan bool
}

func Scrape(id int, name string) {
    fmt.Println(fmt.Sprintf("%v", id) + ": Received " + name)
}

func InitScraper(id int, scraperQueue chan chan Link) Scraper {
    return Scraper {
        Id: id,
        Link: make(chan Link),
        ScraperQueue: scraperQueue,
        QuitChan: make(chan bool),
    }
}

func main() {
    linkQueue = make(chan Link, 2000)

    numScrapers := 2

    scraperQueue = make(chan chan Link, numScrapers)

    for i := 0; i < numScrapers; i++ {
        s := InitScraper(i+1, scraperQueue)
        s.Start()
    }

    go func() {
        for {
            select {
            case link := <-linkQueue:
                go func() {
                    scraper := <-scraperQueue
                    scraper <- link
                }()
            }
        }
    }()

    CycleDirectory(1)

    wg.Wait()

    fmt.Println("Done")
}