<?xml version="1.0" encoding="UTF-8"?>
<config>
  <smtpServer>smtp.163.com</smtpServer>
  <smtpPort>25</smtpPort>
  <sender>user@163.com</sender>
  <senderPasswd>123456</senderPasswd>
  <receivers flag="true">
    <user>Mike_Zhang@live.com</user>
    <user>test1@qq.com</user>
  </receivers>
</config>

package main

import (
  "encoding/xml"
  "fmt"
  "io/ioutil"
  "os"
)

type SConfig struct {
  XMLName  xml.Name `xml:"config"` // 指定最外层的标签为config
  SmtpServer string `xml:"smtpServer"` // 读取smtpServer配置项，并将结果保存到SmtpServer变量中
  SmtpPort int `xml:"smtpPort"`
  Sender string `xml:"sender"`
  SenderPasswd string `xml:"senderPasswd"`
  Receivers SReceivers `xml:"receivers"` // 读取receivers标签下的内容，以结构方式获取
}

type SReceivers struct {
  Flag string `xml:"flag,attr"` // 读取flag属性
  User []string `xml:"user"` // 读取user数组
}

func main() {
  file, err := os.Open("default.xml") // For read access.
  if err != nil {
    fmt.Printf("error: %v", err)
    return
  }
  defer file.Close()
  data, err := ioutil.ReadAll(file)
  if err != nil {
    fmt.Printf("error: %v", err)
    return
  }
  v := SConfig{}
  err = xml.Unmarshal(data, &v)
  if err != nil {
    fmt.Printf("error: %v", err)
    return
  }

  fmt.Println(v)
  fmt.Println("SmtpServer : ",v.SmtpServer)
  fmt.Println("SmtpPort : ",v.SmtpPort)
  fmt.Println("Sender : ",v.Sender)
  fmt.Println("SenderPasswd : ",v.SenderPasswd)
  fmt.Println("Receivers.Flag : ",v.Receivers.Flag)
  for i,element := range v.Receivers.User {
    fmt.Println(i,element)
  }
}

[root@local t1]# ls
default.xml xmlCnfTest1.go
[root@local t1]# go run xmlCnfTest1.go
{{ config} smtp.163.com 25 user@163.com 123456 {true [Mike_Zhang@live.com test1@qq.com]}}
SmtpServer : smtp.163.com
SmtpPort : 25
Sender : user@163.com
SenderPasswd : 123456
Receivers.Flag : true
Mike_Zhang@live.com
test1@qq.com
[root@local t1]#

err = xml.Unmarshal(data, &v)

err = xml.Unmarshal([]byte(ConfigContent), &v) // ConfigContent为xml字符串