Java tutorial
//package com.java2s; import java.io.ByteArrayOutputStream; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Node; public class Main { public static byte[] toByteArray(Node doc) { try { Transformer transformer = TransformerFactory.newInstance().newTransformer(); transformer.setOutputProperty(OutputKeys.INDENT, "yes"); ByteArrayOutputStream os = new ByteArrayOutputStream(); StreamResult result = new StreamResult(os); DOMSource source = new DOMSource(doc); transformer.transform(source, result); return os.toByteArray(); } catch (Exception e) { throw new RuntimeException(e); } } }