Golang 发送http POST/GET请求时设置header

package main
import (
    "fmt"
    "io/ioutil"
    "net/http"                                                                                                                                                     
    "os"
    "encoding/json"
)

func main() { //生成client 参数为默认
    client := &http.Client{}
    //生成要访问的url
    url := "http://somesite/somepath/"
    //提交请求
    reqest, err := http.NewRequest("GET", url, nil)

    //增加header选项
    reqest.Header.Add("Cookie", "xxxxxx")
    reqest.Header.Add("User-Agent", "xxx")
    reqest.Header.Add("X-Requested-With", "xxxx")

    if err != nil {
        panic(err)
    }   
    //处理返回结果
    response, _ := client.Do(reqest)
    defer response.Body.Close()

//Golang发送post请求
 post := "{"待发送"："json"}"
    fmt.Println(post)   
     var jsonstr = []byte(post) //转换二进制   
      buffer:= bytes.NewBuffer(jsonstr)    
       request, err := http.NewRequest("POST",api_url, buffer)  
         if err != nil {        fmt.Printf("%v", err)       
          return queryobj, err    }    request.Header.Set("Content-Type", "application/json;charset=UTF-8")  //添加请求头   
           client := http.Client{} //创建客户端   
            resp, err :=client.Do(request.WithContext(context.TODO())) //发送请求   
             if err != nil {      
               fmt.Printf("%v", err)     
                  return queryobj, err    }  
             respBytes, err := ioutil.ReadAll(resp.Body)    if err != nil {        fmt.Printf("%v", err)        return queryobj, err    }