求教:爬虫在多ip主机运行的时候,如何切换对外请求的ip

🙆‍

package main

import (
    "context"
    "flag"
    "io"
    "net"
    "net/http"
    "os"
)

func main() {
    src := flag.String("ip", "", "src ip")
    dst := flag.String("url", "https://www.baidu.com", "get url")
    flag.Parse()

    resp, err := IpGet(*src, *dst)
    if err != nil {
        panic(err)
    }
    //goland:noinspection GoUnhandledErrorResult
    defer resp.Body.Close()

    _, err = io.Copy(os.Stdout, resp.Body)
    if err != nil {
        panic(err)
    }
}

func IpGet(srcIP, url string) (*http.Response, error) {
    c := http.Client{
        Transport: &http.Transport{
            DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
                ra, err := net.ResolveTCPAddr(network, addr)
                if err != nil {
                    return nil, err
                }
                var la *net.TCPAddr
                if srcIP != "" {
                    // 指定本地源网卡"IP:0",端口为0表示自动分配
                    la, err = net.ResolveTCPAddr(network, srcIP)
                    if err != nil {
                        return nil, err
                    }
                }
                return net.DialTCP(network, la, ra)
            },
        },
    }
    return c.Get(url)
}

执行go run main.go -ip 1.2.3.4:0，表示用IP为1.2.3.4端口随机的源地址请求，而该IP就是你要指定网卡的IP就可以了。

<code>package main

import ( "fmt" "net/http" ) func main() { ipList := [5]string{"192.168.1.2", "192.168.1.3", "192.168.1.4", "192.168.1.5", "192.168.1.6"} searchUrl := "http://www.baidu.com/s?ie=utf-8&f=8&rsv_bp=1&rsv_idx=1&tn=baidu&wd=1221&#34; searchRequest, err := http.NewRequest("GET", searchUrl, nil) if err != nil { fmt.Println(err) } client := &http.Client{} searchIndex, err := client.Do(searchRequest) if err != nil { fmt.Println(err) } defer searchIndex.Body.Close() fmt.Print(searchIndex) } </code>

请教楼上大佬,假如我服务器的ip地址事先存入了数组ipList,如何在发起http请求的时候,使用这些ip来对外访问呢.