使用go的net/http实现读取web页面

package main

import (

 "fmt"

 "io/ioutil" //[1]

 "net/http" //[2]

 "os" //[3]

 "path/filepath" // [4]

)

func main() {

 if len(os.Args) != 2 {

 fmt.Printf("useage:%s http://url", filepath.Base(os.Args[0]))

 os.Exit(1)

 }

 resp, err := http.Get(os.Args[1])

 if err != nil {

 fmt.Println(err) //go语言会内含详细的错误描述，可以尝试不同的参数来测试

 os.Exit(2)

 }

 defer resp.Body.Close() //The client must close the response body when finished with it: 

 body, err2 := ioutil.ReadAll(resp.Body) //此处使用了包【1】

 if err2 != nil {

 fmt.Println(err2)

 os.Exit(3)

 }

 fmt.Printf("%s", body)

}

##生成程序测试

getwebpage.exe
useage:getwebpage.exe http://url

getwebpage.exe http://ww
Get http://ww: dial tcp: GetAddrInfoW: No such host is known.

getwebpage.exe htt
Get htt: unsupported protocol scheme ""

相关说明 

在DOS里执行命令 “godoc -http=:8000”后可以查到相关包

http://127.0.0.1:8000/pkg/net/http/

http://127.0.0.1:8000/pkg/io/ioutil/#ReadAll

Package http provides HTTP client and server implementations.

Get, Head, Post, and PostForm make HTTP (or HTTPS) requests:

resp, err := http.Get("http://example.com/")

...

resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)

...

resp, err := http.PostForm("http://example.com/form",

  url.Values{"key": {"Value"}, "id": {"123"}})

//func ReadAll(r io.Reader) ([]byte, error)

ReadAll reads from r until an error or EOF and returns the data it read. A successful call returns err == nil, not err == EOF. Because ReadAll is defined to read from src until EOF, it does not treat an EOF from Read as an error to be reported.