Golang : Save map/struct to JSON or XML file


Tags : golang XML json save-to-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



Tags : golang XML json save-to-file

By Adam Ng

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.


Advertisement