Gorm格式化time.Time时间字段

Gorm自带的time.Time类型JSON默认输出RFC3339Nano格式的，但是如果想改为yyyy-MM-dd HHss形式的时间格式，需要定制MarshalJSON了。

这个问题一般用不到特殊时间字段的根本不会发现，我这边场景里需要用到接收前端传来的会议开始时间和结束时间，一般也都是yyyy-MM-dd HHss，所以time.Time自然是转换不了，接下来一起重写下Marshal和UnMarshal时间吧。

再插一句，如果前端没有携带这两个字段，系统会自动给你塞一个0000-00-00 00:00:00.000，这显然也不是我们想要的，没有我们为null就行了。

我们先声明了一个LocalTime的别名，然后绑定了函数MarshalJSON和UnMarshalJSON，用于在序列化和反序列化时调用。

/*
 @Author   : Uyynot
 @Email    : uyynot@qq.com
 @Time     : 2023/10/12 11:08
 @File     : base.go
 @Project  : nunu_project
 @Desc     :
 */
 package model
 
 import (
   "database/sql/driver"
   "fmt"
   "github.com/pkg/errors"
   "strings"
   "time"
 )
 // LocalTime起一个别名
 type LocalTime time.Time
 
 // 序列化时间格式
 func (t *LocalTime) MarshalJSON() ([]byte, error) {
  // LocalTime 转换成 time.Time 类型
   tTime := time.Time(*t)
   return []byte(fmt.Sprintf("\"%v\"", tTime.Format("2006-01-02 15:04:05"))), nil
 }
 // 反序列化时间处理
 func (t *LocalTime) UnmarshalJSON(data []byte) error {
   //去除接收的str收尾多余的"
   timeStr := strings.Trim(string(data), "\"")
   //转为当前服务器所在时区时间
   t1, err := time.ParseInLocation("2006-01-02 15:04:05", timeStr, time.Local)
 
   // time.Time转换为LocalTime类型
   *t = LocalTime(t1)
   if err != nil {
   return errors.New("时间格式有误，转换失败")
   }
   return nil
 
 }
 
 func (t LocalTime) Value() (driver.Value, error) {
   var zeroTime time.Time
   tlt := time.Time(t)
   //判断给定时间是否和默认零时间的时间戳相同
   if tlt.UnixMicro() == zeroTime.UnixMicro() {
   return nil, nil
   }
   return tlt, nil
 }
 
 func (t *LocalTime) Scan(v any) error {
   if value, ok := v.(time.Time); ok {
   *t = LocalTime(value)
   return nil
   }
   return fmt.Errorf("不能转换 %V 为时间戳", v)
 }

定义model

 type Metting struct {
   gorm.Model
   Title     string     `gorm:"not null" json:"title"`
   Icon      string     `gorm:"not null" json:"icon"`
   TimeStart LocalTime `json:"time_start"`
   TimeEnd   LocalTime `json:"time_end"`
 }

以上我们响应结果就变为了

 {
  "ID": 10,
  "CreatedAt": "2023-10-12T12:42:55.435+08:00",
  "UpdatedAt": "2023-10-12T12:42:55.435+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "dddd",
  "time_start": null,
  "time_end": null
 },
 {
  "ID": 11,
  "CreatedAt": "2023-10-12T13:25:24.389+08:00",
  "UpdatedAt": "2023-10-12T13:25:24.389+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "",
  "time_start": null,
  "time_end": "2023-02-02 15:11:22"
 }
``````go
 {
  "ID": 10,
  "CreatedAt": "2023-10-12T12:42:55.435+08:00",
  "UpdatedAt": "2023-10-12T12:42:55.435+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "dddd",
  "time_start": null,
  "time_end": null
 },
 {
  "ID": 11,
  "CreatedAt": "2023-10-12T13:25:24.389+08:00",
  "UpdatedAt": "2023-10-12T13:25:24.389+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "",
  "time_start": null,
  "time_end": "2023-02-02 15:11:22"
 }
``````go
 {
  "ID": 10,
  "CreatedAt": "2023-10-12T12:42:55.435+08:00",
  "UpdatedAt": "2023-10-12T12:42:55.435+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "dddd",
  "time_start": null,
  "time_end": null
 },
 {
  "ID": 11,
  "CreatedAt": "2023-10-12T13:25:24.389+08:00",
  "UpdatedAt": "2023-10-12T13:25:24.389+08:00",
  "DeletedAt": null,
  "title": "dddd",
  "icon": "",
  "time_start": null,
  "time_end": "2023-02-02 15:11:22"
 }