Golang XML解析教程：高效处理同时包含属性与字符数据值的元素

<RootLevel status="new" timestamp="1383259529" xmlns="http://someplace.com">
    <Item active="1" status="new" itemid="451254">
        <SubItem active="1" recent="false" usertext="No idea" id="78421">
            <SubItemField active="1" ready="no" type="1">1.4</SubItemField>
            <SubItemField active="1" ready="yes" type="2">4.5</SubItemField>
        </SubItem>
    </Item>
</RootLevel>

// 仅获取属性，无法获取元素值
type SubItemField struct {
    Active bool   `xml:"active,attr"`
    Ready  string `xml:"ready,attr"`
    Type   int    `xml:"type,attr"`
}

// 仅获取元素值，无法获取属性
type SubItem struct {
    // ... 其他字段
    SubItemField []float32 // 仅能获取值
}

type SubItemField struct {
    Value  float32 `xml:",chardata"` // 捕获元素内部的字符数据值
    Active bool    `xml:"active,attr"`
    Ready  string  `xml:"ready,attr"`
    Type   int     `xml:"type,attr"`
}

package main

import (
    "encoding/xml"
    "fmt"
)

// RootLevel 结构体映射根元素
type RootLevel struct {
    XMLName   xml.Name `xml:"RootLevel"`
    Status    string   `xml:"status,attr"`
    Timestamp int64    `xml:"timestamp,attr"`
    Items     []Item   `xml:"Item"`
}

// Item 结构体映射 Item 元素
type Item struct {
    Active string    `xml:"active,attr"` // XML中是"1"，故使用string，或实现自定义Unmarshaler
    Status string    `xml:"status,attr"`
    ItemID int       `xml:"itemid,attr"`
    SubItem []SubItem `xml:"SubItem"`
}

// SubItem 结构体映射 SubItem 元素
type SubItem struct {
    Active   string `xml:"active,attr"` // XML中是"1"，故使用string
    Recent   string `xml:"recent,attr"` // XML中是"false"，故使用string
    UserText string `xml:"usertext,attr"`
    ID       int    `xml:"id,attr"`
    SubItemFields []SubItemField `xml:"SubItemField"` // 注意这里是复数，因为有多个SubItemField
}

// SubItemField 结构体映射 SubItemField 元素，同时获取值和属性
type SubItemField struct {
    Value  float32 `xml:",chardata"` // 捕获元素内部的字符数据值
    Active bool    `xml:"active,attr"` // encoding/xml会自动将"1"或"0"解析为bool
    Ready  string  `xml:"ready,attr"`
    Type   int     `xml:"type,attr"`
}

func main() {
    xmlData := `
<RootLevel status="new" timestamp="1383259529" xmlns="http://someplace.com">
    <Item active="1" status="new" itemid="451254">
        <SubItem active="1" recent="false" usertext="No idea" id="78421">
            <SubItemField active="1" ready="no" type="1">1.4</SubItemField>
            <SubItemField active="1" ready="yes" type="2">4.5</SubItemField>
        </SubItem>
    </Item>
</RootLevel>`

    var root RootLevel
    err := xml.Unmarshal([]byte(xmlData), &root)
    if err != nil {
        fmt.Printf("XML解析失败: %v\n", err)
        return
    }

    fmt.Printf("RootLevel Status: %s, Timestamp: %d\n", root.Status, root.Timestamp)

    for _, item := range root.Items {
        fmt.Printf("  Item ID: %d, Active: %s, Status: %s\n", item.ItemID, item.Active, item.Status)
        for _, subItem := range item.SubItem {
            fmt.Printf("    SubItem ID: %d, Active: %s, Recent: %s, UserText: %s\n", subItem.ID, subItem.Active, subItem.Recent, subItem.UserText)
            for _, subItemField := range subItem.SubItemFields {
                fmt.Printf("      SubItemField Value: %.1f, Active: %t, Ready: %s, Type: %d\n",
                    subItemField.Value, subItemField.Active, subItemField.Ready, subItemField.Type)
            }
        }
    }
}

RootLevel Status: new, Timestamp: 1383259529
  Item ID: 451254, Active: 1, Status: new
    SubItem ID: 78421, Active: 1, Recent: false, UserText: No idea
      SubItemField Value: 1.4, Active: true, Ready: no, Type: 1
      SubItemField Value: 4.5, Active: true, Ready: yes, Type: 2