我正在 golang 中开发一个 rest api，并且能够将数据编码为 xml 和 json。我拥有的结构有多个记录，但 xml 编码不会为这些记录添加根。因此 XML 无效。

我看到一些问题可以通过设置 XMLName 来解决，但我认为这只会将我的客户类型更改为其他类型。

我仍然可以尝试的是在 xml 编码字节周围添加并连接。但我不确定我是否必须这样做。

编辑:显然 XML 编码正确，因为我正在编码一个内部有多个对象的结构。然后编码为每个对象创建单独的 XML 文档。那么问题是其余客户端可以使用什么来使用数据，或者在休息响应中发送多个 xml 文档是不好的做法吗？浏览器无法显示生成的 xml。

要返回单个 XML 文档，我必须将列表放入一个结构中，然后可以对其进行编码。我不确定如何以这种方式使用 sqlx 初始化结构。

添加以下代码不起作用:

type custs struct {
    List []Customer `xml:"Customer"`
}

custs customers.[]Customer =  []Customer{}

代码:

package main

import (
    "database/sql"
    json "encoding/json"
    "encoding/xml"
    "fmt"
    "net/http"
)

type Customer struct {
    CustomerID int            `db:"CustomerId"`
    FirstName  string         `db:"FirstName"`
    LastName   string         `db:"LastName"`
    Company    sql.NullString `db:"Company"`
}

func tstSQLite(w http.ResponseWriter, r *http.Request) {

    contentType := r.Header.Get("Content-type")

    Customers := []Customer{}

    var err error

    fmt.Print("executing query")
    err = chinookdb.Select(&Customers, "SELECT CustomerId, FirstName,LastName, Company FROM customers")

    if err != nil {
        panic(err)
    }

    for _, g := range Customers {
        fmt.Println("FirstName:", g.FirstName, "LastName:", g.LastName)
    }

    var data []byte

    if contentType == "application/xml" {
        data, err = xml.Marshal(Customers)
    }

    if contentType == "application/json" || contentType != "application/xml" {
        data, err = json.Marshal(Customers)
    }


    w.Header().Set("Content-Type", "application/json")
    w.Write(data)
}

我得到的是以下 xml:

   <Customer>
      <CustomerID>1</CustomerID>
      <FirstName>Luís</FirstName>
      <LastName>Gonçalves</LastName>
      <Company>
         <String>Embraer - Empresa Brasileira de Aeronáutica S.A.</String>
         <Valid>true</Valid>
      </Company>
   </Customer>
   <Customer>
      <CustomerID>2</CustomerID>
      <FirstName>Leonie</FirstName>
      <LastName>Köhler</LastName>
      <Company>
         <String />
         <Valid>false</Valid>
      </Company>
   </Customer>
   <Customer>
      <CustomerID>3</CustomerID>
      <FirstName>François</FirstName>
      <LastName>Tremblay</LastName>
      <Company>
         <String />
         <Valid>false</Valid>
      </Company>
   </Customer>

但我觉得应该是这样的:

<Customers>
   <Customer>
      <CustomerID>1</CustomerID>
      <FirstName>Luís</FirstName>
      <LastName>Gonçalves</LastName>
      <Company>
         <String>Embraer - Empresa Brasileira de Aeronáutica S.A.</String>
         <Valid>true</Valid>
      </Company>
   </Customer>
   <Customer>
      <CustomerID>2</CustomerID>
      <FirstName>Leonie</FirstName>
      <LastName>Köhler</LastName>
      <Company>
         <String />
         <Valid>false</Valid>
      </Company>
   </Customer>
   <Customer>
      <CustomerID>3</CustomerID>
      <FirstName>François</FirstName>
      <LastName>Tremblay</LastName>
      <Company>
         <String />
         <Valid>false</Valid>
      </Company>
   </Customer>
</Customers>

编码的 json 看起来是正确的，因为客户在括号中:

[
   {
      "CustomerID":1,
      "FirstName":"Luís",
      "LastName":"Gonçalves",
      "Company":{
         "String":"Embraer - Empresa Brasileira de Aeronáutica S.A.",
         "Valid":true
      }
   },
   {
      "CustomerID":2,
      "FirstName":"Leonie",
      "LastName":"Köhler",
      "Company":{
         "String":"",
         "Valid":false
      }
   }
]

最佳答案

您必须将此客户集合包装在另一个结构中作为

package main

import (
    "encoding/xml"
    "fmt"
    "os"
)

func main() {

    type Customer struct {
        XMLName   xml.Name `xml:"Customer"`
        CustomerID int            `db:"CustomerId"`
        FirstName  string         `db:"FirstName"`
        LastName   string         `db:"LastName"`
        Company    string `db:"Company"`
    }

    type Customers struct {
        List []Customer
    }

    csts := []Customer{
        Customer{CustomerID: 1, FirstName: "John", LastName: "Doe", Company: "Demo Company"},
        Customer{CustomerID: 2, FirstName: "John2", LastName: "Doe2", Company: "Demo Company2"},
    }


    res := Customers {
        List: csts,
    }

    output, err := xml.MarshalIndent(res, "  ", "    ")
    if err != nil {
        fmt.Printf("error: %v\n", err)
    }

    os.Stdout.Write(output)
}

默认它可以采用构造的名称。您还可以使用 xml.Name 类型自定义名称。

关于XML Marshalling 无需 Root 即可生成 XML，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55933508/