package main

import (
	"encoding/json"
	"strconv"
    "fmt"
)

type TheLong struct {
	Value     int64
}

type Test struct {
	Name      string  `json:"name"`
	Name2     string  `json:"name2"`
	Name3     string  `json:"name3,omitempty"`
	Age       int32   `json:"age"`
	NotSer    string  `json:"-"`
	Bool      bool    `json:"bool"`
	BoolInStr bool    `json:"bool_in_str,string"`
	Long      int64   `json:"long"`
	Long2     TheLong `json:"long2"`
}

// https://www.cnblogs.com/yorkyang/p/8990570.html
func (l *TheLong) MarshalJSON() (data []byte, err error) {
	fmt.Println("------")//??
    if l != nil {
        data = []byte(strconv.FormatInt(l.Value, 10))
    }
    return
}
func (l *TheLong) UnmarshalJSON(data []byte) error {
	v, err := strconv.ParseInt(string(data), 10, 64)
	if err != nil {
		return err
	}
	l.Value = v
    return nil
}
 

func main() {
	t := Test {
		Name: "hatter",
		Name2: "",
		Name3: "",
		Age: 18,
		NotSer: "not ser!",
		Bool: true,
		BoolInStr: true,
		Long: 342438204823084023,
		Long2: TheLong { Value: 1111111111111111111 },
	}
	s, err := json.Marshal(t)
	if err != nil {
		fmt.Println("ERROR: ", err)
		return
	}
	fmt.Println("JSON: ", string(s))
}