Go语言中处理动态XML标签的Unmarshal教程

<unit_amount_in_cents>
 <USD type="integer">4000</USD>
 <GBP type="integer">5000</GBP>
</unit_amount_in_cents>
<setup_fee_in_cents>
 <EUR type="integer">6000</EUR>
</setup_fee_in_cents>

type Currency struct {
    XMLName xml.Name `xml:""` // 尝试捕获标签名
    Amount  string   `xml:",chardata"`
}

type CurrencyArray struct {
    CurrencyList []Currency `xml:"?"` // 这里需要处理动态标签
}

package main

import (
    "encoding/xml"
    "errors"
    "fmt"
    "strconv"
    "time"
)

// Currency 定义了货币元素结构，XMLName用于捕获动态标签名
type Currency struct {
    XMLName xml.Name `xml:""`         // 捕获动态标签名，如 "USD", "GBP"
    Type    string   `xml:"type,attr"` // 捕获type属性
    Amount  string   `xml:",chardata"` // 捕获元素内容
}

// CurrencyArray 包含一个Currency切片，并使用xml:",any"处理动态子元素
type CurrencyArray struct {
    CurrencyList []Currency `xml:",any"` // 关键：使用",any"捕获所有未匹配的子元素
}

// AddCurrency 方法用于向CurrencyArray中添加货币，便于Marshal
func (c *CurrencyArray) AddCurrency(currency string, amount int) {
    newc := Currency{Amount: fmt.Sprintf("%v", amount), Type: "integer"}
    newc.XMLName.Local = currency // 设置动态标签名
    c.CurrencyList = append(c.CurrencyList, newc)
}

// GetCurrencyValue 方法用于从CurrencyArray中获取指定货币的值
func (c *CurrencyArray) GetCurrencyValue(currency string) (value int, e error) {
    for _, v := range c.CurrencyList {
        if v.XMLName.Local == currency {
            value, e = strconv.Atoi(v.Amount)
            return
        }
    }
    e = errors.New(fmt.Sprintf("%s not found", currency))
    return
}

// Plan 结构体包含动态货币数组
type Plan struct {
    XMLName              xml.Name      `xml:"plan"`
    Name                 string        `xml:"name,omitempty"`
    PlanCode             string        `xml:"plan_code,omitempty"`
    Description          string        `xml:"description,omitempty"`
    SuccessUrl           string        `xml:"success_url,omitempty"`
    CancelUrl            string        `xml:"cancel_url,omitempty"`
    DisplayDonationAmounts bool        `xml:"display_donation_amounts,omitempty"`
    DisplayQuantity      bool          `xml:"display_quantity,omitempty"`
    DisplayPhoneNumber   bool          `xml:"display_phone_number,omitempty"`
    BypassHostedConfirmation bool      `xml:"bypass_hosted_confirmation,omitempty"`
    UnitName             string        `xml:"unit_name,omitempty"`
    PaymentPageTOSLink   string        `xml:"payment_page_tos_link,omitempty"`
    PlanIntervalLength   int           `xml:"plan_interval_length,omitempty"`
    PlanIntervalUnit     string        `xml:"plan_interval_unit,omitempty"`
    AccountingCode       string        `xml:"accounting_code,omitempty"`
    CreatedAt            *time.Time    `xml:"created_at,omitempty"`
    SetupFeeInCents      CurrencyArray `xml:"setup_fee_in_cents,omitempty"` // 包含动态货币数组
    UnitAmountInCents    CurrencyArray `xml:"unit_amount_in_cents,omitempty"` // 包含动态货币数组
}

func main() {
    // 示例XML数据，包含动态货币标签
    xmlData := `
<plan>
    <name>Basic Plan</name>
    <plan_code>BP001</plan_code>
    <setup_fee_in_cents>
        <USD type="integer">4000</USD>
        <GBP type="integer">3500</GBP>
    </setup_fee_in_cents>
    <unit_amount_in_cents>
        <USD type="integer">1000</USD>
        <EUR type="integer">900</EUR>
    </unit_amount_in_cents>
</plan>`

    var plan Plan
    err := xml.Unmarshal([]byte(xmlData), &plan)
    if err != nil {
        fmt.Printf("Unmarshal error: %v\n", err)
        return
    }

    fmt.Println("--- Unmarshaled Plan Data ---")
    fmt.Printf("Plan Name: %s\n", plan.Name)
    fmt.Printf("Plan Code: %s\n", plan.PlanCode)

    fmt.Println("\nSetup Fee In Cents:")
    for _, c := range plan.SetupFeeInCents.CurrencyList {
        fmt.Printf("  Currency: %s, Amount: %s, Type: %s\n", c.XMLName.Local, c.Amount, c.Type)
    }
    usdSetupFee, err := plan.SetupFeeInCents.GetCurrencyValue("USD")
    if err == nil {
        fmt.Printf("  USD Setup Fee: %d\n", usdSetupFee)
    }

    fmt.Println("\nUnit Amount In Cents:")
    for _, c := range plan.UnitAmountInCents.CurrencyList {
        fmt.Printf("  Currency: %s, Amount: %s, Type: %s\n", c.XMLName.Local, c.Amount, c.Type)
    }
    eurUnitAmount, err := plan.UnitAmountInCents.GetCurrencyValue("EUR")
    if err == nil {
        fmt.Printf("  EUR Unit Amount: %d\n", eurUnitAmount)
    }

    // 演示Marshal回XML
    fmt.Println("\n--- Marshaling back to XML ---")
    // 假设我们修改或添加一些数据
    plan.UnitAmountInCents.AddCurrency("JPY", 12000)
    plan.SetupFeeInCents.AddCurrency("CAD", 3000)

    outputXML, err := xml.MarshalIndent(plan, "", "    ")
    if err != nil {
        fmt.Printf("Marshal error: %v\n", err)
        return
    }
    fmt.Println(string(outputXML))
}