步骤

1. 组装链接
2. 爬取内容
3. 把内容写入文件

package main

import(
    "fmt"
    "net/http"
    "strconv"
    "os"
)

// 爬取网页内容
func HttpGet(url string) (result string, err error){
    resp, err1 := http.Get(url)
    if err1 != nil{
        err = err1
        return
    }

    defer resp.Body.Close()

    // 读取网页body内容
    buf := make([]byte, 1024*4)
    for{
        n, err := resp.Body.Read(buf)
        if n == 0 { // 读取结束或者报错
            fmt.Println("resp.Body.Read err = ", err)
            break
        }

        result += string(buf[:n])
    }

    return
}

// 爬取一个网页
func SpiderPage(i int, page chan<- int){
    // 组装链接
        url := "https://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F&ie=utf-8&pn="+strconv.Itoa((i-1)*50)
        fmt.Printf("正在爬第%d个网页: %s\n", i, url)
        // 爬取内容
        result, err := HttpGet(url)
        if err!=nil{
            fmt.Println("err = ", err)
            return
        }

        // 把内容写入文件
        fileName := strconv.Itoa(i) + ".html"
        f, err1 := os.Create(fileName)
        if err1 != nil{
            fmt.Println("os.Create err1 = ", err1)
            return
        }
        f.WriteString(result) // 写内容
        f.Close() // 关闭文件

        page <- i
}

func DoWork(start, end int){
    fmt.Printf("正在爬取 %d 到 %d 的页面\n", start, end)

    page := make(chan int)

    for i := start; i <= end; i++ {
        go SpiderPage(i, page)
    }

    for i := start; i <= end; i++ {
        fmt.Printf("第%d个网页爬取完成\n", <-page)
    }
}

func main(){
    var start, end int
    fmt.Printf("请输入起始页(>=1):")
    fmt.Scan(&start)
    fmt.Printf("请输入终止页(>=起始页):")
    fmt.Scan(&end)

    DoWork(start, end)
}