EpochTimeで入っているjsonをstructに読み込むためのサンプル

main.go

package main

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

type Hoge struct {
	At *EpochTime `json:"at"`
}

type EpochTime time.Time

func (t *EpochTime) UnmarshalJSON(buf []byte) error {
	value, err := strconv.ParseInt(string(buf), 10, 64)
	if err != nil {
		return err
	}
	*t = EpochTime(time.Unix(value, 0))
	return nil
}

func (t *EpochTime) MarshalJSON() ([]byte, error) {
	epoch := (time.Time)(*t).Unix()
	bs := []byte(strconv.FormatInt(epoch, 10))
	return bs, nil
}

func (t *EpochTime) String() string {
	return (time.Time)(*t).String()
}

func main() {
	var hoge Hoge
	err := json.Unmarshal([]byte("{\"at\": 1437999924}"), &hoge)
	if err != nil {
		fmt.Println(err.Error())
	}
	fmt.Println(hoge.At)

	buf, err := json.Marshal(&hoge)
	if err != nil {
		fmt.Println(err.Error())
	}
	fmt.Println(string(buf))
}