在golang中，如何编码包含空格的xml参数？

I have this xml api construct I need to use (this construct is not defined by me and I cannot change it):

<path><farmer id="ME7"/></path>

In go I have:

type Path struct {
  XMLName xml.Name `xml:"path"`
  FarmerId string `xml:"farmer id,attr"`
}

pMux := &Path{FarmerId: "ME7"}

However go encodes pMux and prints it as this:

<path xmlns:farmer="farmer" farmer:id="ME7" </path>

What I want is this:

<path><farmer id="ME7"/> </path>

How can I achieve this?

Thx

The XML is invalid, but if you really need it to come out like that, use a regular expression to fix it afterward. Here is an example.

I am assuming that you really want the open tag valid like so <path farmer id="ME7"></path>, instead of not having the open tag valid as you posted <path farmer id="ME7" </path>, but either way is doable with regex.

BTW, your question is inconsistent about what you want. You start with wanting <path><farmer id="ME7"></path>, which @eugenioy 's answer will accommodate. Then end with "What I want is this: <path farmer id="ME7" </path>". Which my answer is geared toward.

https://play.golang.org/p/A-sJhIgFZW

package main

import (
    "encoding/xml"
    "fmt"
    "regexp"
)

type Path struct {
    XMLName  xml.Name `xml:"path"`
    Farmer   string   `xml:"farmer,attr"`
    FarmerId string   `xml:"id,attr"`
}

func main() {
    path := &Path{
        FarmerId: "ME7",
    }
    data, err := xml.Marshal(path)
    if err != nil {
        fmt.Println(err)
        return
    }

    strData := string(data)

    // fix with regex
    reg := regexp.MustCompile(`(farmer)(="")`)
    strData = reg.ReplaceAllString(strData, "$1")
    fmt.Println(strData) // <path farmer id="ME7"></path>
}

That's not valid XML.

I would double check the API contract you mention since it's unlikely they require invalid XML.

The closest you can get to that is this valid XML.

<path><farmer id="ME7"></farmer></path>

In order to generate the above (valid) XML, you should define your types as:

type Farmer struct {
   XMLName   xml.Name    `xml:"farmer"`
   Id        string      `xml:"id,attr"`
}

type Path struct {
    XMLName xml.Name `xml:"path"`
    Farmer  Farmer   `xml:"farmer"`
}

And then create the value as:

v := Path{Farmer: Farmer{Id: "ME7"}}

See here for a running example: https://play.golang.org/p/abEqMc6HdK