golang gorm中格式化时间问题详解

package utils
import (
 "time"
 //"strconv"
 "fmt"
 "database/sql/driver"
 "strconv"
)
type LocalTime struct {
 time.Time
}
func (t LocalTime) MarshalJSON() ([]byte, error) {
 //格式化秒
 seconds := t.Unix()
 return []byte(strconv.FormatInt(seconds, 10)), nil
}
func (t LocalTime) Value() (driver.Value, error) {
 var zeroTime time.Time
 if t.Time.UnixNano() == zeroTime.UnixNano() {
 return nil, nil
 }
 return t.Time, nil
}
func (t *LocalTime) Scan(v interface{}) error {
 value, ok := v.(time.Time)
 if ok {
 *t = LocalTime{Time: value}
 return nil
 }
 return fmt.Errorf("can not convert %v to timestamp", v)
}

type TestDao struct{
   Id    uint    `gorm:"primary_key,AUTO_INCREMENT" json:"id"`
 CreatedAt  LocalTime `json:"-"`
 UpdatedAt  LocalTime `json:"update_at"`
 DeletedAt  *LocalTime `json:"-"`
}