Golang无法将XML映射到Struct

I want to map XML data to Struct object. I have following code:

package main
import (
    "encoding/xml"
    "fmt"
)

func main() {
    type FileDetails struct {
        XMLName   xml.Name `xml:"FileDetails"`
        FileName string
        FileSize string
    }

    type DataRequest struct {
        XMLName   xml.Name `xml:"Data"`
        DataRequestList []FileDetails
    }

    type Request struct {
        XMLName   xml.Name `xml:"Request"`
        DataReqObject DataRequest `xml:"Data"`
    }
    req := Request{}

    data := `
        <Request>
            <Data>
                <FileDetails>
                    <FileName>abc</FileSize>
                    <FileSize>10</FileSize>
                </FileDetails>
                <FileDetails>
                    <FileName>pqr</FileSize>
                    <FileSize>20</FileSize>
                </FileDetails>
            </Data>
        </Request>
    `
    err := xml.Unmarshal([]byte(data), &req)
    if err != nil {
        fmt.Printf("error: %v", err)
        return
    }
    fmt.Printf("XMLName: %#v
", req.XMLName)
    fmt.Printf("XMLName: %v
", req.DataReqObject)
    fmt.Printf("XMLName: %v
", req.DataReqObject.DataRequestList[0])
}

This can also be accessed here: https://play.golang.org/p/VAMM9M2CejH

I'm getting following output with the above code:

XMLName: xml.Name{Space:"", Local:"Request"}
Data: {{ Data} []}
panic: runtime error: index out of range

Do the structs need to have diffferent structure for my data? Why is this mapping failing?

Three problems with your snippet:

#1

The tag xml:"FileDetails" is missing on DataRequestList

#2

The FileDetails struct does not match your xml in the provided playground link!

#3

<FileName> tag is closed with </FileSize> tag!

Go playground working example!