Question

从mongodb检索到数组对象。数据如下所示： -

[{
  1 
  fruits 
  Apple 
  Apple is my favorite fruit.
 }
 {
  2 
  colors 
  Red 
  Red color is always charming.
 } 
 {
  3 
  flowers 
  Lotus 
  It is one of the most beautiful flowers in this world.
 }]

这是检索上述数据的代码结构是：

type Item struct {
  Id          int    `json:"id"`
  Category    string `json:"category"`
  Name        string `json:"name"`
  Description string `json:"description"`
}
type Items []Item

func GetData(Query interface{}) (result Items, err error) {
    mongoSession := ConnectDb()
    sessionCopy := mongoSession.Copy()
    defer sessionCopy.Close()
    getCollection := mongoSession.DB("custom").C("custom")
    err = getCollection.Find(Query).All(&result)
    if err != nil {
        return result, err
    }
    return result, nil
}
/*
 *  Retrieve the data used by main function
 */
func retrieve(c *gin.Context) {
  //mongoSession := ConnectDb()
  conditions := bson.M{}
  data, err :=GetData(conditions)
  if err != nil {
    fmt.Println("There is somthing wrong")
  }
  arrange(data)
  return
}

func arrange(data Items) {
  pagesJson, err := json.Marshal(data)
  if err != nil {
    log.Fatal("Cannot encode to JSON ", err)
  }
  fmt.Println(string(pagesJson))
}

运行json.Marshal，输出如下所示：

[{
  "id":1,
  "category":"fruits",
  "name":"Apple",
  "description":"Apple is my favorite fruit."
},
{
  "id":2,
  "category":"colors",
  "name":"Red",
  "description":"Red color is always charming."
},
{
  "id":3,
  "category":"flowers",
  "name":"Lotus",
  "description":"It is one of the most beautiful flowers in this world."
}]

预期输出

{
  "id":1,
  "category":"fruits",
  "name":"Apple",
  "description":"Apple is my favorite fruit."
}
{
  "id":2,
  "category":"colors",
  "name":"Red",
  "description":"Red color is always charming."
}
{
  "id":3,
  "category":"flowers",
  "name":"Lotus",
  "description":"It is one of the most beautiful flowers in this world."
}

问题是数据在我使用的数组对象中我需要{}之间的字符串结构数据，如上所示。我之前发过这个问题，但没有得到任何成功的答案。我从很多时候开始尝试帮助我，谢谢你。

Answer 1

根据OP讨论的内容，对结构Items进行编组将得到：

[{
  "id":1,
  "category":"fruits",
  "name":"Apple",
  "description":"Apple is my favorite fruit."
},
{
  "id":2,
  "category":"colors",
  "name":"Red",
  "description":"Red color is always charming."
},
{
  "id":3,
  "category":"flowers",
  "name":"Lotus",
  "description":"It is one of the most beautiful flowers in this world."
}]

由此，OP希望得到一个如下所示的字符串：

{
  "id":1,
  "category":"fruits",
  "name":"Apple",
  "description":"Apple is my favorite fruit."
},
{
  "id":2,
  "category":"colors",
  "name":"Red",
  "description":"Red color is always charming."
},
{
  "id":3,
  "category":"flowers",
  "name":"Lotus",
  "description":"It is one of the most beautiful flowers in this world."
}

我考虑过两种方法：

循环浏览项目并将每个封送的项目附加到字符串中（显然效率不高）

func getMyString(items Items) (string, error) {

    var buffer bytes.Buffer
    var err error
    var b []byte

    for _, item := range items {
        b, err = json.Marshal(item)
        if err != nil {
            return "", err
        }

        buffer.WriteString(string(b) + ",")
    }

    s := strings.TrimSpace(buffer.String())
    // trim last comma
    s = s[:len(s)-1]

    return s, nil
}

或者只是修剪前后方括号：

func getMyString2(items Items) (string, error) {

    b, err := json.Marshal(items)
    if err != nil {
        return "", err
    }

    s := string(b)
    s = strings.TrimSpace(s)
    // trim leading and trailing spaces
    s = s[1 : len(s)-1]
    return s, nil
}

代码链接：https://play.golang.org/p/F1SUYJZEn_n

编辑：由于OP希望它与众不同，我修改了第1号方法以符合要求：

func getMyString(items Items) (string, error) {
    var buffer bytes.Buffer
    var err error
    var b []byte

    for _, item := range items {
        b, err = json.Marshal(item)
        if err != nil {
            return "", err
        }
        // use space to separate each json string in the array
        buffer.WriteString(string(b) + " ")
    }

    s := strings.TrimSpace(buffer.String())

    return s, nil
}

链接到新代码：https://play.golang.org/p/dVvsQlsRqZO

如何使用golang将数组对象数据转换为字符串格式数据？

1 个答案: