如何在Go中为外部HTML模板设置变量？

package main

import (
    "html/template"
    "net/http"
)

type Data struct {
    Name string
    Age  int
}

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        // 创建一个包含变量的结构体
        data := Data{
            Name: "John",
            Age:  30,
        }

        // 解析外部HTML模板文件
        tmpl, err := template.ParseFiles("template.html")
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        // 传递数据给模板并生成HTML输出
        err = tmpl.Execute(w, data)
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }
    })

    http.ListenAndServe(":8080", nil)
}