golang JSON

test_json.go

package main

import (
    "fmt"
    "encoding/json"
    
    "github.com/mitchellh/mapstructure"
)

type A struct {
    A int 
    B int
    Hello string
}

func main() {
    var str = `
{
  "a": 123,
  "b": 456,
  "c": {
    "d": true,
    "e": null  
  },
  "e": [ 123, 456, { "x": { "y": 444}} ],
  "HeLLO": "hello"
}    
    `
    var data map[string]interface{}
    json.Unmarshal([]byte(str), &data)
    fmt.Println(data)

    if b, err := json.Marshal(data); err != nil {
        fmt.Println(err)
    } else {
        fmt.Println(string(b))
    }
    
    var a A
    if err := mapstructure.Decode(data, &a); err != nil {
        fmt.Println(err)
    } else {
        fmt.Println(a)
    }
}