go Http Post 发送文件流

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))
}