想在 Go 中使用 gorm 从 mysql 生成 json 输出答案

【问题标题】：Wants to generate json output from mysql using gorm in Go想在 Go 中使用 gorm 从 mysql 生成 json 输出
【发布时间】：2021-08-04 22:05:00
【问题描述】：

所以我试图从我的数据库（即 MySQL）中获取数据。我能够完成访问数据库的步骤，但问题是我想以 JSON 格式获取输出，但我做了一些研究但没有得到结果，所以任何人都可以指导或帮助我，获取 MySQL使用 GORM 的 json 格式的数据。这是我编写的代码示例。

package main

import (
    "fmt"

    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/mysql" //This must be introduced! !
)

type k_movie struct {
    Id         uint32
    Title      string `gorm:"default:''"`
    Url_name   string `gorm:"default:''"`
    K_score    string ``
    Poster_url string ``
}

func main() {

    db, errDb := gorm.Open("mysql", "root:xyz@123@(127.0.0.1)/dbdump?charset=utf8mb4&loc=Local")

    if errDb != nil {
        fmt.Println(errDb)
    }
    defer db.Close() //Close the database connection after use up

    db.LogMode(true) //Open sql debug mode

    //SELECT * FROM `k_movies`  WHERE (id>0 and id<.....)
    var movies []k_movie
    db.Where("id>? and id<?", 0, 103697).Limit(3).Find(&movies)
    fmt.Println(movies)

    //Get the number
    total := 0
    db.Model(&k_movie{}).Count(&total)
    fmt.Println(total)

    var infos []k_movie //Define an array to receive multiple results
    db.Where("Id in (?)", []uint32{1, 2, 3, 4, 5, 6, 7, 8}).Find(&infos)
    fmt.Println(infos)
    fmt.Println(len(infos)) //Number of results

    var notValue []k_movie
    db.Where("id=?", 3).Find(&notValue)
    if len(notValue) == 0 {
        fmt.Println("No data found!")
    } else {
        fmt.Println(notValue)
    }

}

我得到这种格式的输出。

kumardivyanshu@Divyanshus-MacBook-Air ~/myproject/src/github.com/gorm_mysql % go run test.go

(/Users/kumardivyanshu/myproject/src/github.com/gorm_mysql/test.go:31) 
[2021-05-13 08:59:45]  [3.89ms]  SELECT * FROM `k_movies`  WHERE (id>0 and id<103697) LIMIT 3  
[3 rows affected or returned ] 
[{1 Golmaal: Fun Unlimited golmaal-fun-unlimited 847 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/32b7385e1e616d7ba3d11e1bee255ecce638a136} {2 Dabangg 2 dabangg-2 425 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/1420c4d6f817d2b923cd8b55c81bdb9d9fd1eca0} {3 Force force 519 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/cd1dc247da9d16e194f4bfb09d99f4dedfb2de00}]

(/Users/kumardivyanshu/myproject/src/github.com/gorm_mysql/test.go:36) 
[2021-05-13 08:59:45]  [20.22ms]  SELECT count(*) FROM `k_movies`    
[0 rows affected or returned ] 
103697

(/Users/kumardivyanshu/myproject/src/github.com/gorm_mysql/test.go:40) 
[2021-05-13 08:59:45]  [2.32ms]  SELECT * FROM `k_movies`  WHERE (Id in (1,2,3,4,5,6,7,8))  
[8 rows affected or returned ] 
[{1 Golmaal: Fun Unlimited golmaal-fun-unlimited 847 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/32b7385e1e616d7ba3d11e1bee255ecce638a136} {2 Dabangg 2 dabangg-2 425 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/1420c4d6f817d2b923cd8b55c81bdb9d9fd1eca0} {3 Force force 519 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/cd1dc247da9d16e194f4bfb09d99f4dedfb2de00} {4 Eega eega 906 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/08aef7d961d4699bf2d12a7c854b6b32d1445247} {5 Fukrey fukrey 672 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/5d14bd2fb0166f4bb9ab919e31b69f2605f366aa} {6 London Paris New York london-paris-new-york 323 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/222d8a6b5c76b1d3cfa0b93d4bcf1a1f16f5e199} {7 Bhaag Milkha Bhaag bhaag-milkha-bhaag 963 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/efa8b86c753ae0110cc3e82006fadabb06f1486c} {8 Bobby Jasoos bobby-jasoos 244 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/0e9540d4c962ec33d8b63c0c563e7b64169122e0}]
8

(/Users/kumardivyanshu/myproject/src/github.com/gorm_mysql/test.go:45) 
[2021-05-13 08:59:45]  [1.56ms]  SELECT * FROM `k_movies`  WHERE (id=3)  
[1 rows affected or returned ] 
[{3 Force force 519 https://movieassetsdigital.sgp1.cdn.digitaloceanspaces.com/thumb/cd1dc247da9d16e194f4bfb09d99f4dedfb2de00}]

【问题讨论】：

标签： mysql json go go-gorm

【解决方案1】：

您需要在结构上定义json tag，因此您可以使用json.Marshal 来获取呈现json 对象的[]byte 切片。

示例取自Go by example:

type Response2 struct {
  Page   int      `json:"page"`
  Fruits []string `json:"fruits"`
}

res2D := &Response2{
    Page:   1,
    Fruits: []string{"apple", "peach", "pear"}}
res2B, _ := json.Marshal(res2D)
fmt.Println(string(res2B))
That would print:

{"page":1,"fruits":["apple","peach","pear"]}

【讨论】：