我在一个 API 中使用 Go 来获取我所在城市的公交车频率，但是当我尝试使 HTTP Get 访问许多 URL 时，我有点卡在了线程上。 如果没有并发，程序需要超过 16 分钟才能完成 1500 个 url 调用以获取 HTTP 状态代码，我试图使用并发，但在阅读了很多帖子后我不明白 goroutines 是如何工作的......

想法是制作一个函数并更改请求的数量，如下所示:

 go getBusPostStatus(600, 800) 

但我完全坚持...

代码如下:

package main 
 
import ( 
"fmt" 
"net/http" 
"strconv" 
"time" 
) 
var i int = 0 
var convStr string 
var message = make(chan string) 
 
/*func main(){ 
    for i = 0; i < 1500; i++ { 
        z = strconv.Itoa(i) 
        url := "http://www.urbanosdezaragoza.es/frm_esquemaparadatime.php?poste=" + z 
        resp, err := http.Get(url) 
        if err != nil { 
            fmt.Println("Houston, we've got problems") 
        }else{ 
            if resp.StatusCode == 200{ 
                fmt.Println("OK: El poste "+z+" existe") 
            }else{ 
                fmt.Println("WARN: El poste "+z+" NO existe") 
            } 
        } 
    } 
}*/ 
 
//Return 2 houndred posts 
func returnTH(c chan string){ 
 for i = 0; i < 200; i++ {   
    convStr = strconv.Itoa(i) 
    url := "http://www.urbanosdezaragoza.es/frm_esquemaparadatime.php?poste=" + convStr 
    resp, err := http.Get(url) 
    if err != nil { 
        fmt.Println("Houston, we've got problems") 
    }else{ 
        if resp.StatusCode == 200{ 
            //fmt.Println("OK: El poste "+z+" existe") 
            c <- "OK: The bus post "+convStr+" exists" 
        }else{ 
            //fmt.Println("WARN: El poste "+z+" NO existe") 
            c <- "WARN: The bus post "+convStr+" does not exist" 
        }    
    } 
  } 
} 
func returnFH(z chan string){ 
  for i = 201; i < 400; i++ {    
   convStr = strconv.Itoa(i) 
   url := "http://www.urbanosdezaragoza.es/frm_esquemaparadatime.php?poste=" + convStr 
    resp, err := http.Get(url) 
    if err != nil { 
        fmt.Println("Houston, we've got problems") 
    }else{ 
        if resp.StatusCode == 200{ 
            //fmt.Println("OK: El poste "+z+" existe") 
            z <- "OK: The bus post "+convStr+" exists" 
        }else{ 
            //fmt.Println("WARN: El poste "+z+" NO existe") 
            z <- "WARN: The bus post "+convStr+" does not exist" 
        }    
    }  
  } 
} 
 
func threadPrint(c, z chan string){ 
   for { 
       threadOne := <- c 
       threadTwo := <- z 
       fmt.Println(threadOne) 
       fmt.Println(threadTwo) 
   } 
} 
func main(){ 
    start := time.Now() 
    var c chan string = make(chan string) 
    var z chan string = make(chan string) 
    //for i = 0; i < 1500; i++{ 
    go returnTH(c) 
    go returnFH(z) 
    go threadPrint(c,z) 
    /*go getBusPostStatus(400, 600) 
    go getBusPostStatus(600, 800) 
    go getBusPostStatus(800, 1000) 
    go getBusPostStatus(1000, 1200) 
    go getBusPostStatus(1200, 1400) 
    go getBusPostStatus(1400, 1500)*/ 
    //} 
    timeExec:= time.Since(start) 
    fmt.Println("Time to exec code = ", timeExec) 
 
    /*var input string 
    fmt.Scanln(&input) 
    fmt.Println("done")*/ 
} 

非常感谢!

请您参考如下方法:

以下是一个简化的示例代码，它使用 goroutine 和 channel 并发请求 100 次并打印结果。希望这段代码有所帮助。

package main 
 
import ( 
    "fmt" 
    "math/rand" 
    "time" 
) 
 
func main() { 
    rep := 100 
    results := make(chan string) 
 
    // Use goroutine to send multiple time-consuming jobs to the channel. 
    for i := 0; i < rep; i++ { 
        go func(num int) { 
            results <- mockHTTPRequest(num) 
        }(i) 
    } 
 
    // Receive results from the channel and use them. 
    for i := 0; i < rep; i++ { 
        fmt.Println(<-results) 
    } 
} 
 
func mockHTTPRequest(num int) string { 
    timeDelay := rand.Intn(5000) 
    time.Sleep(time.Duration(timeDelay) * time.Millisecond) 
    if timeDelay%2 == 0 { 
        return fmt.Sprintf("OK: The bus post %v exists", num) 
    } 
    return fmt.Sprintf("WARN: The bus post %v does not exist", num) 
} 

您可以在 https://play.golang.org/p/RR34roRIl4 上运行此代码.