useful to convert struct to map use specific tag as key

[golang]iter struct & get tag

package main

import (
	"fmt"
	"reflect"
)

type User struct{
	Name string `json:"name" bson:"b_name"`
	Age int `json:"age" bson:"b_age"`
}

func main() {
	var u User
	t:=reflect.TypeOf(u)
	for i:=0;i<t.NumField();i++{
		sf:=t.Field(i)
		fmt.Println(sf.Tag.Get("json"),",",sf.Tag.Get("bson"))
	}
}
# 输出
name , b_name
age , b_age