Golang : Save map/struct to JSON or XML file

Previous tutorial on converting map/slice/array to JSON or XML format is for output to web via net/http package. This tutorial is a slight modification and save the output to JSON or XML file instead.

Here you go!

 package main

 import (
 "encoding/json"
 "encoding/xml"
 "fmt"
 "io"
 "os"
 "strconv"
 )

 type Person struct {
 Name string `json:"name"`
 Age  int `json:"age"`
 }

 func main() {

 // create and populate a map from dummy JSON data

 dataStr := `{"Name":"Dummy","Age":0}`

 personMap := make(map[string]interface{})

 err := json.Unmarshal([]byte(dataStr), &personMap)

 if err != nil {
 panic(err)
 }

 var onePerson Person

 // convert map to Person struct
 onePerson.Name = fmt.Sprintf("%s", personMap["Name"])
 onePerson.Age, _ = strconv.Atoi(fmt.Sprintf("%v", personMap["Age"]))

 jsonData, err := json.Marshal(onePerson)

 if err != nil {
 panic(err)
 }

 // sanity check
 fmt.Println(string(jsonData))

 // write to JSON file

 jsonFile, err := os.Create("./Person.json")

 if err != nil {
 panic(err)
 }
 defer jsonFile.Close()

 jsonFile.Write(jsonData)
 jsonFile.Close()
 fmt.Println("JSON data written to ", jsonFile.Name())

 // write to XML file

 xmlFile, err := os.Create("./Person.xml")
 if err != nil {
 panic(err)
 }
 defer xmlFile.Close()

 xmlWriter := io.Writer(xmlFile)

 enc := xml.NewEncoder(xmlWriter)
 enc.Indent("  ", " ")
 if err := enc.Encode(onePerson); err != nil {
 fmt.Printf("error: %v\n", err)
 }

 xmlFile.Close()
 fmt.Println("XML data written to ", xmlFile.Name())

 }

Output:

{"name":"Dummy","age":0}

JSON data written to ./Person.json

XML data written to ./Person.xml

References:

https://www.socketloop.com/tutorials/golang-create-new-xml-file

https://www.socketloop.com/tutorials/golang-xml-to-json-example

https://www.socketloop.com/tutorials/golang-covert-map-slice-array-to-json-xml-format