go 发送http请求

package main
import (
  "net/http"
  "io/ioutil"
  "fmt"
  "strings"
  "net/url"
  "bytes"
  "encoding/json"
)
func main() {
  urls := "http://www.baidu.com/"
  var data = map[string]interface{}{}
  res := 1
  var resp *http.Response
  var err error
  //-------------------------发起请求------------------------------------
  switch  res{
  case 1:
    // get请求
    resp, err = http.Get(urls)
  case 2:
    // post发送json
    datas, _ := json.Marshal(data)
    resp, err = http.Post(urls, "application/json", bytes.NewBuffer(datas))
  case 3:
    // post发送from表单
    datas := make(url.Values)
    for key, value := range data {
      datas[string(key)] = []string{value.(string)}
    }
    resp, err = http.PostForm(urls, datas)
  case 4:
    // 创建请求设置参数
    datas := url.Values{
      "name": {"fei"},
    }
    req, err := http.NewRequest("POST",urls, strings.NewReader(datas.Encode()))
    if err != nil {
      // handle error
    }
    req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
    req.Header.Add("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36")
    client := &http.Client{}
    resp, err = client.Do(req)
  }
  //-------------------------发起请求成功------------------------------------
  if err != nil {
    fmt.Println(err.Error())
  }
  defer resp.Body.Close()
  body, err := ioutil.ReadAll(resp.Body)
  if err != nil {
    fmt.Println(err.Error())
  }
  fmt.Println(string(body))
  //解析返回body的话直接用断言就可以
}