golang json decode with field name

Question

For following JSON

{
    "Jon": {
       "Age": 15
    },
    "Mary": {
       "Age": 17
    } 
}

how can i map it into golang struct, normally, the structure will be

type Person struct {
    Name string `json:??,string`
    Age int `json:Age, int`
}

as the json field name is the attribute of struct, thank you in advance.

See an example how to unmarshal json into go struct eagain.net/articles/go-json-array-to-struct — dmitryro
– dmitryro, Commented Feb 10, 2018 at 1:08

Adrian · Accepted Answer · 2018-02-10 01:52:54Z

4

You have to use custom JSON marshalling

package main

    import (
        "encoding/json"
        "log"
        "fmt"
    )

    type Person struct {
        Name string `json:??,string`
        Age  int    `json:Age, int`
    }

    type People map[string]*Person

    func (p *People) UnmarshalJSON(data []byte) error {
        var transient = make(map[string]*Person)
        err := json.Unmarshal(data, &transient)
        if err != nil {
            return err
        }
        for k, v := range transient {
            v.Name = k
            (*p)[k] = v
        }
        return nil
    }

    func main() {

        jsonInput := `
        {
            "Jon": {
        "Age": 15
        },
            "Mary": {
        "Age": 17
        }
        }
    `

        var people People = make(map[string]*Person)

        err := people.UnmarshalJSON([]byte(jsonInput))
        if err != nil {
            log.Fatal(err)
        }

        for _, person := range people {
            fmt.Printf("%v -> %v\n", person.Name, person.Age)
        }
    }

edited Feb 10, 2018 at 1:52

answered Feb 10, 2018 at 1:47

Adrian

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1 Comment

Himanshu Over a year ago

why you have used pointer receiver in the UnmarshalJSON function

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