Go语言国际化（i18n）实践指南

{
  "item_count": {
    "one": "You have {{.Count}} item.",
    "other": "You have {{.Count}} items."
  }
}

{
  "welcome_message": "Welcome, {{.UserName}}!"
}

import (
    "github.com/nicksnyder/go-i18n/v2/i18n"
    "golang.org/x/text/language"
)

func main() {
    bundle := i18n.NewBundle(language.English)
    // 加载翻译文件
    bundle.LoadMessageFile("en.json")

    // 创建本地化器，通常根据用户请求的语言来创建
    localizer := i18n.NewLocalizer(bundle, language.English.String())

    // 翻译并插入变量
    welcomeMsg, err := localizer.Localize(&i18n.LocalizeConfig{
        MessageID: "welcome_message",
        TemplateData: map[string]interface{}{
            "UserName": "Alice",
        },
    })
    if err != nil {
        // 处理错误
    }
    println(welcomeMsg) // Output: Welcome, Alice!
}

[
  {
    "ID": "hello_world",
    "Other": "Hello, World!"
  },
  {
    "ID": "greeting_with_name",
    "Other": "Hello, {{.Name}}!"
  },
  {
    "ID": "unread_messages",
    "One": "You have one unread message.",
    "Other": "You have {{.Count}} unread messages."
  }
]

package main

import (
    "fmt"
    "net/http"
    "path/filepath"

    "github.com/nicksnyder/go-i18n/v2/i18n"
    "golang.org/x/text/language"
)

var bundle *i18n.Bundle

func init() {
    // 1. 初始化i18n Bundle，指定默认语言（通常是英语）
    bundle = i18n.NewBundle(language.English)

    // 2. 设置JSON格式解析器
    bundle.RegisterUnmarshalFunc("json", json.Unmarshal)

    // 3. 加载所有语言的翻译文件
    // 假设翻译文件位于 ./active.en.json, ./active.zh.json 等
    // 实际项目中，这些文件路径可能来自配置或通过遍历目录获取
    dir := "./locales" // 假设翻译文件在项目根目录下的 locales 文件夹
    files := []string{"active.en.json", "active.zh.json"} // 示例文件列表

    for _, file := range files {
        filePath := filepath.Join(dir, file)
        bundle.LoadMessageFile(filePath)
        fmt.Printf("Loaded message file: %s\n", filePath)
    }
}

func main() {
    // 模拟一个HTTP请求处理函数
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        // 4. 根据请求的 Accept-Language 头创建Localizer
        // ParseAcceptLanguageFromHeader 是一个简化函数，实际可能更复杂
        acceptLangs := r.Header.Get("Accept-Language")
        localizer := i18n.NewLocalizer(bundle, acceptLangs)

        // 5. 进行翻译
        // 翻译一个简单的问候语
        helloMsg, err := localizer.Localize(&i18n.LocalizeConfig{
            MessageID: "hello_world",
        })
        if err != nil {
            helloMsg = "Error: " + err.Error()
        }

        // 翻译一个带变量的问候语
        name := "Go Developer"
        greetingMsg, err := localizer.Localize(&i18n.LocalizeConfig{
            MessageID: "greeting_with_name",
            TemplateData: map[string]interface{}{
                "Name": name,
            },
        })
        if err != nil {
            greetingMsg = "Error: " + err.Error()
        }

        // 翻译一个带复数形式的消息
        unreadCount := 5
        unreadMsg, err := localizer.Localize(&i18n.LocalizeConfig{
            MessageID:   "unread_messages",
            PluralCount: unreadCount,
            TemplateData: map[string]interface{}{
                "Count": unreadCount,
            },
        })
        if err != nil {
            unreadMsg = "Error: " + err.Error()
        }

        fmt.Fprintf(w, "%s\n%s\n%s\n", helloMsg, greetingMsg, unreadMsg)
    })

    fmt.Println("Server listening on :8080")
    http.ListenAndServe(":8080", nil)
}

// 示例翻译文件内容 (locales/active.en.json)
/*
[
  {
    "ID": "hello_world",
    "Other": "Hello, World!"
  },
  {
    "ID": "greeting_with_name",
    "Other": "Hello, {{.Name}}!"
  },
  {
    "ID": "unread_messages",
    "One": "You have one unread message.",
    "Other": "You have {{.Count}} unread messages."
  }
]
*/

// 示例翻译文件内容 (locales/active.zh.json)
/*
[
  {
    "ID": "hello_world",
    "Other": "你好，世界！"
  },
  {
    "ID": "greeting_with_name",
    "Other": "你好，{{.Name}}！"
  },
  {
    "ID": "unread_messages",
    "One": "你有一条未读消息。",
    "Other": "你有{{.Count}}条未读消息。"
  }
]
*/