package main

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

type A struct {
    Name string `json:"name"`
    Age  string `json:"name"`
}

type B struct {
    Bname string `json:"bName"`
}
type C struct {
    Cname string `json:"cName"`
}

type D struct {
    DataA A `json:"dataA"`
    DataB B `json:"dataB"`
 

    DataC C `json:"dataC"`
}

func main() {

    var d D
    d.DataA.Age = "DataA.Age"
    d.DataA.Name = "DataA.Name"
    d.DataB.Bname = "DataB.Bname"
    d.DataC.Cname = "DataC.Cname"

    buffer, err := json.Marshal(d)
    if err != nil {
        log.Println(err)
    }
    var jsonStruct map[string
 
]interface{}
    if err := json.Unmarshal(buffer, &jsonStruct); err != nil {
        log.Println(err)
    }

    jsonStruct["token"] = "--------------------------"

    buffer, err = json.Marshal(jsonStruct)
    if err != nil {
        log.Println(err)
    }

    fmt.Println(string(buffer[:]))

}
//----------------------------------
 

{"dataA":{},"dataB":{"bName":"DataB.Bname"},"dataC":{"cName":"DataC.Cname"},"token":"--------------------------"}