the-way-to-go_ZH_CN/eBook/15.3.md

15.3 访问并读取页面

在下边这个程序中，数组中的url都将被访问：会发送一个简单的http.Head()请求查看返回值；它的声明如下：func Head(url string) (r *Response, err error)

返回状态码会被打印出来。

示例 15.7 poll_url.go：

package main

import (
	"fmt"
	"net/http"
)

var urls = []string{
	"http://www.google.com/",
	"http://golang.org/",
	"http://blog.golang.org/",
}

func main() {
	// Execute an HTTP HEAD request for all url's
	// and returns the HTTP status string or an error string.
	for _, url := range urls {
		resp, err := http.Head(url)
		if err != nil {
			fmt.Println("Error:", url, err)
		}
		fmt.Print(url, ": ", resp.Status)
	}
}

输出为：

http://www.google.com/ : 302 Found
http://golang.org/ : 200 OK
http://blog.golang.org/ : 200 OK

译者注 由于国内的网络环境现状，很有可能见到如下超时错误提示：

Error: http://www.google.com/ Head http://www.google.com/: dial tcp 216.58.221.100:80: connectex: A connection attempt failed because the connected pa
rty did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

在下边的程序中我们使用http.Get()获取网页内容； Get的返回值res中的Body属性包含了网页内容，然后我们用ioutil.ReadAll把它读出来：

示例 15.8 http_fetch.go：