01—封装err函数

package main
import (
    "net"
    "fmt"
    "os"
)
func errFunc(err error, info string)  {
    if err != nil {
        fmt.Println(info, err)
        //return                    // 返回当前函数调用
        //runtime.Goexit()            // 结束当前go程
        os.Exit(1)            // 将当前进程结束。
    }
}
func main()  {
    listener, err := net.Listen("tcp", "127.0.0.1:8000")
    errFunc(err, "net.Listen err:")
    defer listener.Close()
    conn, err := listener.Accept()
    errFunc(err, "Accpet err:")
    defer conn.Close()
    buf := make([]byte, 4096)
    n, err := conn.Read(buf)
    if n == 0 {
        return
    }
    errFunc(err, "conn.Read")
    fmt.Printf("|%s|\n", string(buf[:n]))
}

02-模拟浏览器访问

# 将下面代码替换成以下代码
resp,err := http.Get(url)
defer resp.Body.Close()
# 替换为
client := &http.Client{}
req, err1 := http.NewRequest("GET", url, nil)
if err1 != nil {
    err = err1
    return
}
req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36")
resp, err2 := client.Do(req)
if err2 != nil {
    err = err2
    return
}
defer resp.Body.Close()

03-匹配换行

ret1 := regexp.MustCompile(`<li class=" col-4">\r\n.*<a  href="(?s:(.*?))"`)

04-读取html文件

func main() {
    addr := ":8888"
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        f, _ := os.Open("./template/index.html")
        io.Copy(w, f)
    })
    http.ListenAndServe(addr, nil)
}