Serializing Java Objects to XML

HI !

in my last post i talked about java -Costume- Serialization, so for today i will continue on that topic but this time i will write objects to a more human readable format “XML”.

today’s post is more of an introduction to a class (two classes actually ) XMLEncoder and XMLDecoder .

XMLEncoder is an complementary alternative to the ObjectOutputStream Class . instead of series of bytes you get a textual format .

XMLEncoder Write Objects with the Java Beans Convention in mind, it’s not necessary to implement the Serializable interface, but your Object must have these two properties :

1- public empty constructor

2- getters and setters for every protected/private property

as per how the XMLEncoder works , it uses reflexion to know the state of each field and convert them to XML format, let’s look at an example to make it clearer :

let’s Say we have a Settings Class that contains information about a certain user :

	// simple class written as a Java bean
	public class Settings {
	private String settings1;
	private Integer settings2;
	public Settings(){}
	public Settings(String settings1, Integer settings2) {
	this.settings1 = settings1;
	this.settings2 = settings2;
	}
	public String getSettings1() {
	return settings1;
	}
	public void setSettings1(String settings1) {
	this.settings1 = settings1;
	}
	public Integer getSettings2() {
	return settings2;
	}
	public void setSettings2(Integer settings2) {
	this.settings2 = settings2;
	}
	@Override
	public String toString() {
	return "Settings{" +
	"settings1='" + settings1 + '\'' +
	", settings2=" + settings2 +
	'}';
	}
	}

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Settings.java

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now we Create A Serializer class that will handle the serialization and deserialization process :

	import java.beans.ExceptionListener;
	import java.beans.XMLDecoder;
	import java.beans.XMLEncoder;
	import java.io.FileInputStream;
	import java.io.FileOutputStream;
	/**
	* @author Mehdi Maick
	* Created by mac on 17/11/2016.
	*/
	public class Serializer {
	// Serialize the given Object
	public static void serializeToXml(Settings settings) throws Exception {
	FileOutputStream f = new FileOutputStream("settings.xml");
	XMLEncoder encoder = new XMLEncoder(f);
	encoder.setExceptionListener(new ExceptionListener() {
	public void exceptionThrown(Exception e) {
	System.out.println("an Exception Occured " + e.getMessage());
	}
	});
	encoder.writeObject(settings);
	encoder.close();
	f.close();
	}
	// Deserialize an Object
	public static Settings desrializeFromXml() throws Exception {
	FileInputStream fis = new FileInputStream("settings.xml");
	XMLDecoder decoder = new XMLDecoder(fis);
	Settings decodedSettings = (Settings) decoder.readObject();
	decoder.close();
	fis.close();
	return decodedSettings;
	}
	//main to test
	public static void main(String[] args) throws Exception {
	Settings s = new Settings("user settings", 98);
	serializeToXml(s);
	Settings same = desrializeFromXml();
	System.out.println(same);
	}
	}

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Serializer.java

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this will create a settings.xml file this is the content :

	<?xml version="1.0" encoding="UTF-8"?>
	<java version="1.8.0_60" class="java.beans.XMLDecoder">
	<object class="lib.Settings">
	<void property="settings1">
	<string>user settings</string>
	</void>
	<void property="settings2">
	<int>98</int>
	</void>
	</object>
	</java>

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settings.xml

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magic isn’t it .

Well there you have it Writing Objects to Xml for more advanced Usage please check out this tutorial .  Happy Coding 😀 …