golang 结构体内嵌结构体序列化填充

看我上一篇随笔 https://www.cnblogs.com/zengxm/p/13473340.html

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其中使用mysql原始语句查询结果并返回

上一篇随笔代码

并想直接映射到结构体中,后来发现结构体序列化时有个坑

这次实际操作了一下解决了

代码如下

type Curriculums struct {
    CID         int            `gorm:"column:c_id" json:"cid"`
    UID         int            `gorm:"column:u_id" json:"uid"`
    //TID         int            `gorm:"column:t_id" json:"tid"`
    Name         string        `gorm:"column:c_name" json:"title"`
    Price         float64        `gorm:"column:price" json:"price"`
    Info        string        `gorm:"column:info" json:"info"`
    Image        string        `gorm:"column:c_image" json:"img"`
    CreateTime     *time.Time    `gorm:"column:create_at" json:"at"`
    DeleteTime     *time.Time    `gorm:"column:delete_at" json:"et"`

    AdminDelTime      *time.Time        `gorm:"column:admin_del" json:"a_del"`        // 后台人员删除时间
    Aid               int                `gorm:"column:a_id" json:"aid"`                // 后台执行人信息
}
func (cr *Curriculums)TableName()string{
    return "curriculums"
}
type User struct {
    ID             uint64        `gorm:"column:u_id" json:"uid,omitempty"`
    Nickename     string        `gorm:"column:nickename" json:"nick,omitempty"`
    Username     string        `gorm:"column:username" json:"uname,omitempty"`
    Pswd         string        `gorm:"column:pswd" json:"pswd,omitempty"`
    Status         int            `gorm:"column:status" json:"st,omitempty"`
    RID         int            `gorm:"column:r_id" json:"rid,omitempty"`
    Portrait     string        `gorm:"column:portrait" json:"img,omitempty"`
    CreateTime     *time.Time    `gorm:"column:create_at" json:"at,omitempty"`

    AdminDelTime      *time.Time        `gorm:"column:admin_del" json:"a_del,omitempty"`        // 后台人员删除时间
    Aid               int                `gorm:"column:a_id" json:"aid,omitempty"`                // 后台执行人信息
}
func (u *User)TableName()string{
    return "users"
}

type SelectData struct {
    User
    JsonStr string   `gorm:"column:datas" json:"datas,omitempty"`
    MarshalerData []Curriculums        `json:"datas,omitempty" `
}




func main(){
    var result []SelectData

    SQL := "SELECT u.u_id,u.nickename,u.username, " +
        "CONCAT("[",GROUP_CONCAT('{','"cid":',c.c_id,',"title":"',c.c_name,'","price":',c.price,',"info":"',c.info,'"}'),"]") as datas " +
        "FROM users AS u " +
        "JOIN curriculums AS c " +
        "ON c.u_id = u.u_id " +
        "WHERE c.c_name like '%o%' GROUP BY u.u_id"

    conn.Raw(SQL).Scan(&result)

    for index,_ := range result{

        result[index].JsonStr = strings.Replace(result[index].JsonStr,"
","",-1)

        //fmt.Println(result[index])
        /*
        {{100000 acfun 7745742641  0 0  <nil> <nil> 0} [{"cid":102,"title":"python 学习","price":20.00,"info":"python "},{"cid":103,"title":"golang 学习","price":70.79,"info":"go语言 gin框架"}] {[]}}
        {{100006 giligililllsa666 z99999es  0 0  <nil> <nil> 0} [{"cid":117,"title":"测试保存视频,视频url保存在阿里云oss上","price":9.99,"info":"test in"}] {[]}}
        */
        b,err := json.Marshal(result[index])
        if err != nil {
            panic(err)
        }

        fmt.Println(string(b))
        /*
        上面输出与序列化对比丢失了 datas 数据
        {"uid":100000,"nick":"acfun","uname":"7745742641"}
        {"uid":100006,"nick":"giligililllsa666","uname":"z99999es"} 
       */
    }
}

后来经过排查发现是结构体中内嵌结构体并被命名后产生的坑

type SelectData struct {
    User
    JsonStr string   `gorm:"column:datas" json:"datas,omitempty"`
    MarshalerData []Curriculums        `json:"datas,omitempty" `   # 内嵌结构体被命名了,被命名内嵌结构体如果不指定该命名则不会序列化
    
}

避免产生则需要添加一个中间结构体,修改如下

type Mid struct {
    d []Curriculums        // 小写避免被序列化
}

type SelectData struct {
    User
    JsonStr string   `gorm:"column:datas" json:"datas,omitempty"`   
    //MarshalerData []Curriculums        `json:"datas,omitempty" `
    Mid
}

success:
      {"uid":100000,"nick":"acfun","uname":"7745742641","datas":"[{"cid":102,"title":"python 学习","price":20.00,"info":"python "},{"cid":103,"title":"golang 学习","price":70.79,"info":"go语言 gin框架"}]"}
      {"uid":100006,"nick":"giligililllsa666","uname":"z99999es","datas":"[{"cid":117,"title":"测试保存视频,视频url保存在阿里云oss上
","price":9.99,"info":"test in"}]"}

下次记得使用原始sql语句查询结果并序列化是对内嵌结构体需要注意~~~~~~~~~~~~~~~~

参考资料:

https://www.cnblogs.com/staff/p/13223443.html

https://www.it1352.com/809480.html (重点)

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本笔记自用 而已，如有错误请指正！