golang json 解组 map[string]interface{} 的一部分

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时间:2020-09-03 17:17:03  来源:igfitidea点击:

golang json unmarshal part of map[string]interface{}

jsongo

提问by user10479

I have the following code to try to Unmarshal this json file, however the line json.Unmarshal([]byte(msg["restaurant"]), &restaurant) always gives an error. How can I make Unmarshal ignore the "restaurant" or pass only the "restaurant" data to the Unmarshal function?

我有以下代码尝试解组这个 json 文件,但是 json.Unmarshal([]byte(msg["restaurant"]), &restaurant) 行总是给出错误。如何让 Unmarshal 忽略“餐厅”或仅将“餐厅”数据传递给 Unmarshal 函数?

Thanks!

谢谢!

{
  "restaurant": {
    "name": "Tickets",
    "owner": {
      "name": "Ferran"
    }
  }
}


    file, e := ioutil.ReadFile("./rest_read.json")
    if e != nil {
            fmt.Println("file error")
            os.Exit(1)
    }

    var data interface{}
    json.Unmarshal(file, &data)

    msg := data.(map[string]interface{})
    log.Println(msg)
    log.Println(msg["restaurant"])
    log.Println(reflect.TypeOf(msg["restaurant"]))

    var restaurant Restaurant
    json.Unmarshal([]byte(msg["restaurant"]), &restaurant)

    log.Println("RName: ", restaurant.Name)
    log.Println("Name: ", restaurant.Owner.Name)

采纳答案by Sebastian

I would propose to construct a proper model for your data. This will enable you to cleanly unmarshal your data into a Go struct.

我建议为您的数据构建一个合适的模型。这将使您能够将数据干净地解组为 Go 结构体。

package main

import (
    "encoding/json"
    "fmt"
)

type Restaurant struct {
    Restaurant RestaurantData `json:"restaurant"`
}

type RestaurantData struct {
    Name  string `json:"name"`
    Owner Owner  `json:"owner"`
}

type Owner struct {
    Name string `json:"name"`
}

func main() {
    data := `{"restaurant":{"name":"Tickets","owner":{"name":"Ferran"}}}`
    r := Restaurant{}
    json.Unmarshal([]byte(data), &r)

    fmt.Printf("%+v", r)
}

回答by eric gilbertson

It is possible to do generic unmarshalling ala gson by decoding into an interface and then extracting a top level map from the result, e.g:

可以通过解码为接口然后从结果中提取顶级映射来进行通用解组 ala gson,例如:

var msgMapTemplate interface{}
err := json.Unmarshal([]byte(t.ResponseBody), &msgMapTemplate)
t.AssertEqual(err, nil)
msgMap := msgMapTemplate.(map[string]interface{})

See "decoding arbitrary data" in http://blog.golang.org/json-and-gofor more into.

有关更多信息,请参阅http://blog.golang.org/json-and-go 中的“解码任意数据” 。

回答by Evan

Unmarshalling occurs recursively, so msg["restaurant"]is no longer a json string - it is another map[string]interface{}. If you want to unmarshall directly into a Restaurantobject, you will have to provide a simple wrapper object with a Restaurantmember and unmarshall into that.

解组以递归方式发生,因此msg["restaurant"]不再是 json 字符串 - 它是另一个map[string]interface{}. 如果你想直接解组到一个Restaurant对象中,你必须提供一个带有Restaurant成员的简单包装对象,然后解组到那个对象中。