Golang : Covert map/slice/array to JSON or XML format

Problem :

You have a data struct in map, slice or array format and you have to convert the data to JSON or XML format. How to do that?

Solution :

Convert the map, slice or array data to JSON with json.Marshal() function. In the struct, remember to add struct tags for JSON or XML.

NOTE : Set Content-Type to application/json or application/xml when writing out as HTTP response.

For example :

 package main

 import (

 type KeyPair struct {
  Id int `json:"id"` // <--- json struct tags
  Name string `json:"name"` // <--- json struct tags

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

  KP := KeyPair{Id: 1, Name: "Adam"}

  byte, err := json.Marshal(KP) // <---- here !

  if err != nil {

  w.Header().Set("Content-Type", "application/json") // <---- here !
  fmt.Fprint(w, string(byte))


 func main() {

  http.HandleFunc("/", Home)
  http.ListenAndServe(":8080", nil)

To convert struct data to XML, just change the encoder and field tags to XML equivalent. See https://www.socketloop.com/tutorials/golang-xml-to-json-example for guide.

Happy coding!

  See also : Golang : XML to JSON example

Tags : golang json xml http-response field-tags

Adam Ng By Adam Ng

Get in touch at Google Plus or stay updated on Facebook.

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.