这可能是菜鸟的错误。我有一个带字符串值的 slice 和一个 channel 映射。对于 slice 中的每个字符串，将使用该字符串作为键创建一个 channel 并为其创建一个映射条目。

我观察 channel 并将值传递给其中一个，但从未发现过。

package main

import (
    "fmt"
    "time"
)

type TestStruct struct {
    Test string
}

var channelsMap map[string](chan *TestStruct)

func main() {
    stringsSlice := []string{"value1"}
    channelsMap := make(map[string](chan *TestStruct))

    for _, value := range stringsSlice {
        channelsMap[value] = make(chan *TestStruct, 1)

        go watchChannel(value)
    }

    <-time.After(3 * time.Second)

    testStruct := new(TestStruct)
    testStruct.Test = "Hello!"
    channelsMap["value1"] <- testStruct

    <-time.After(3 * time.Second)
    fmt.Println("Program ended")
}

func watchChannel(channelMapKey string) {
    fmt.Println("Watching channel: " + channelMapKey)

    for channelValue := range channelsMap[channelMapKey] {
        fmt.Printf("Channel '%s' used. Passed value: '%s'\n", channelMapKey, channelValue.Test)
    }

}

Watching channel: value1
Program ended

最佳答案

您的方法有很多问题。

第一个是您要重新声明(“屏蔽”)全局
您的channelsMap函数中的变量main。
(您是否至少完成了一些
most basic intro to Go，您应该没有这样的问题。)

这意味着您的watchChannel(实际上是执行该函数的所有goroutine)都会读取全局channelsMap，而main函数则将其写入本地channelsMap。

接下来发生的情况如下:

package main

import (
    "fmt"
    "sync"
)

type TestStruct struct {
    Test string
}

var channelsMap = make(map[string](chan *TestStruct))

func main() {
    stringsSlice := []string{"value1"}

    var wg sync.WaitGroup

    wg.Add(len(stringsSlice))
    for _, value := range stringsSlice {
        channelsMap[value] = make(chan *TestStruct, 1)

        go watchChannel(value, &wg)
    }

    testStruct := new(TestStruct)
    testStruct.Test = "Hello!"
    channelsMap["value1"] <- testStruct

    wg.Wait()
    fmt.Println("Program ended")
}

func watchChannel(channelMapKey string, wg *sync.WaitGroup) {
    defer wg.Done()
    fmt.Println("Watching channel: " + channelMapKey)

    for channelValue := range channelsMap[channelMapKey] {
        fmt.Printf("Channel '%s' used. Passed value: '%s'\n", channelMapKey, channelValue.Test)
    }

}

package main

import (
    "fmt"
    "sync"
)

type TestStruct struct {
    Test string
}

func main() {
    stringsSlice := []string{"value1"}
    channelsMap := make(map[string](chan *TestStruct))

    var wg sync.WaitGroup

    wg.Add(len(stringsSlice))
    for _, value := range stringsSlice {
        channelsMap[value] = make(chan *TestStruct, 1)

        go watchChannel(value, channelsMap[value], &wg)
    }

    testStruct := new(TestStruct)
    testStruct.Test = "Hello!"
    channelsMap["value1"] <- testStruct

    wg.Wait()
    fmt.Println("Program ended")
}

func watchChannel(channelMapKey string, ch <-chan *TestStruct, wg *sync.WaitGroup) {
    defer wg.Done()
    fmt.Println("Watching channel: " + channelMapKey)

    for channelValue := range ch {
        fmt.Printf("Channel '%s' used. Passed value: '%s'\n", channelMapKey, channelValue.Test)
    }

}

package main

import (
    "fmt"
    "sync"
)

type TestStruct struct {
    Test string
}

func main() {
    var stringsSlice []string
    channelsMap := make(map[string](chan *TestStruct))

    for i := 1; i <= 10; i++ {
        stringsSlice = append(stringsSlice, fmt.Sprintf("value%d", i))
    }

    var wg sync.WaitGroup

    wg.Add(len(stringsSlice))
    for _, value := range stringsSlice {
        channelsMap[value] = make(chan *TestStruct, 1)

        go watchChannel(value, channelsMap[value], &wg)
    }

    for _, value := range stringsSlice {
        testStruct := new(TestStruct)
        testStruct.Test = fmt.Sprint("Hello! ", value)
        channelsMap[value] <- testStruct
    }

    for _, ch := range channelsMap {
        close(ch)
    }

    wg.Wait()
    fmt.Println("Program ended")
}

func watchChannel(channelMapKey string, ch <-chan *TestStruct, wg *sync.WaitGroup) {
    defer wg.Done()
    fmt.Println("Watching channel: " + channelMapKey)

    for channelValue := range ch {
        fmt.Printf("Channel '%s' used. Passed value: '%s'\n", channelMapKey, channelValue.Test)
    }

}

关于go - 无法获取工作 channel 图，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52025354/