go Http Post 发送文件流案例

package main
import (
 "net/http"
 "net/url"
 "fmt"
 "io/ioutil"
 _ "io"
 "bytes"
)
func main() {
 postFile()
}
func post() {
  //这是一个Post 参数会被返回的地址
  strinUrl:="http://localhost:8080/aaa"`这里写代码片`
  resopne,err:= http.PostForm(strinUrl,url.Values{"num":{"456"},"num1":{"123"}})
  if err !=nil {
  fmt.Println("err=",err)
  }
  defer func() {
   resopne.Body.Close()
   fmt.Println("finish")
  }()
  body,err:=ioutil.ReadAll(resopne.Body)
  if err!=nil {
   fmt.Println(" post err=",err)
  }
  fmt.Println(string(body))
}
func postFile(){
 //这是一个Post 参数会被返回的地址
 strinUrl:="http://localhost:8080/aaa"
 byte,err:=ioutil.ReadFile("post.txt")
 resopne,err :=http.Post(strinUrl,"multipart/form-data",bytes.NewReader(byte))
 if err !=nil {
  fmt.Println("err=",err)
 }
 defer func() {
  resopne.Body.Close()
  fmt.Println("finish")
 }()
 body,err:=ioutil.ReadAll(resopne.Body)
 if err!=nil {
  fmt.Println(" post err=",err)
 }
 fmt.Println(string(body))
}

var (
 requestPostURL string = "http://httpbin.org/post"
 // 接收文件的服务自己实现qwq
 // 接收一张图片上传 postman的key file
 imagePostURL  string = "/imageUpload/upload"
 // 接收多张图片上传 postman的key file
 imageMultiPostURL string = "/imageUpload/uploads"
)

// 
func postXWwwFromURLEncoded() {
 client := http.Client{}
 // 不带任何的请求数据post
 // req, err := http.NewRequest(http.MethodPost, requestPostURL, nil)
 // 带数据
 urlValues := url.Values{}
 urlValues.Add("name", "张三")
 urlValues.Add("age", "18")
 reqBody := urlValues.Encode()
 req, err := http.NewRequest(http.MethodPost, requestPostURL, strings.NewReader(reqBody))
 if err != nil {
 log.Println("err")
 }
 resp, err := client.Do(req)
 if err != nil {
 log.Println("err")
 }
 defer resp.Body.Close()
 b, err := ioutil.ReadAll(resp.Body)
 if err != nil {
 log.Println("err")
 }
 fmt.Println(string(b))
 // urlValues := url.Values{}
 // urlValues.Add("name","zhaofan")
 // urlValues.Add("age","22")
 // resp, _ := http.PostForm("http://httpbin.org/post",urlValues)
}

func postRaw() {
 client := http.Client{}
 // 带数据 json 类型
 urlValues := map[string]interface{}{
 "name":  "jack",
 "age":  18,
 "is_active": true,
 }
 b1, _ := json.Marshal(urlValues)
 // b1, _ := json.Marshal(urlValues)
 req, err := http.NewRequest(http.MethodPost, requestPostURL, bytes.NewReader(b1))
 if err != nil {
 log.Println("err")
 }
 resp, err := client.Do(req)
 if err != nil {
 log.Println("err")
 }
 defer resp.Body.Close()
 b, err := ioutil.ReadAll(resp.Body)
 if err != nil {
 log.Println("err")
 }
 fmt.Println(string(b))
}

// multipart/form-data 带普通参数 key-value
func postFormDataWithParams() {
 client := http.Client{}
 // 不带任何的请求数据post
 body := bytes.Buffer{}
 writer := multipart.NewWriter(body)
 params := map[string]string{
 "name": "zhangsan",
 "age": "12",
 }
 for key, val := range params {
 _ = writer.WriteField(key, val)
 }
 writer.Close()
 req, err := http.NewRequest(http.MethodPost, requestPostURL, body)
 if err != nil {
 log.Println("err")
 }
 resp, err := client.Do(req)
 if err != nil {
 log.Println("err")
 }
 defer resp.Body.Close()
 b, err := ioutil.ReadAll(resp.Body)
 if err != nil {
 log.Println("err")
 }
 fmt.Println(string(b))
}

// key:file 里面放一个文件
// multipart/form-data 传一个文件
func postFormDataWithSingleFile() {
 client := http.Client{}
 bodyBuf := bytes.Buffer{}
 bodyWrite := multipart.NewWriter(bodyBuf)
 file, err := os.Open("./images/img.jpg")
 defer file.Close()
 if err != nil {
 log.Println("err")
 }
 // file 为key
 fileWrite, err := bodyWrite.CreateFormFile("file", "img.jpg")
 _, err = io.Copy(fileWrite, file)
 if err != nil {
 log.Println("err")
 }
 bodyWrite.Close() //要关闭，会将w.w.boundary刷写到w.writer中
 // 创建请求
 contentType := bodyWrite.FormDataContentType()
 req, err := http.NewRequest(http.MethodPost, imagePostURL, bodyBuf)
 if err != nil {
 log.Println("err")
 }
 // 设置头
 req.Header.Set("Content-Type", contentType)
 resp, err := client.Do(req)
 if err != nil {
 log.Println("err")
 }
 defer resp.Body.Close()
 b, err := ioutil.ReadAll(resp.Body)
 if err != nil {
 log.Println("err")
 }
 fmt.Println(string(b))
}

// key:file 里面放多个文件
// multipart/form-data 传多个文件
func postFormDataWithMultipartFile() {
 client := http.Client{}
 bodyBuf := bytes.Buffer{}
 bodyWrite := multipart.NewWriter(bodyBuf)
 images := []string{"img.jpg", "img1.jpg"}
 for _, val := range images {
 file, err := os.Open("./images/" + val)
 defer file.Close()
 if err != nil {
 log.Println("err")
 }
 fileWrite, err := bodyWrite.CreateFormFile("file", val)
 _, err = io.Copy(fileWrite, file)
 if err != nil {
 log.Println("err")
 }
 }
 bodyWrite.Close() //要关闭，会将w.w.boundary刷写到w.writer中
 // 创建请求
 req, err := http.NewRequest(http.MethodPost, imagePostURL, bodyBuf)
 if err != nil {
 log.Println("err")
 }
 // 设置头
 contentType := bodyWrite.FormDataContentType()
 req.Header.Set("Content-Type", contentType)
 resp, err := client.Do(req)
 if err != nil {
 log.Println("err")
 }
 defer resp.Body.Close()
 b, err := ioutil.ReadAll(resp.Body)
 if err != nil {
 log.Println("err")
 }
 fmt.Println(string(b))
}

// Content-Type:application/octet-stream,从字面意思得知，只可以上传二进制数据，通常用来上传文件，
// 由于没有键值，所以，一次只能上传一个文件
func postBinary() {
}