Here you can find the source of printDocument(Document doc, boolean prettyPrint)
public static String printDocument(Document doc, boolean prettyPrint) throws IOException, TransformerException
//package com.java2s; /*//from w w w . j a va2 s.c o m * Waltz - Enterprise Architecture * Copyright (C) 2016, 2017 Waltz open source project * See README.md for more information * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import org.w3c.dom.Document; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; public class Main { public static String printDocument(Document doc, boolean prettyPrint) throws IOException, TransformerException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); printDocument(doc, baos, prettyPrint); return new String(baos.toByteArray()); } public static void printDocument(Document doc, OutputStream out, boolean prettyPrint) throws IOException, TransformerException { TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no"); transformer.setOutputProperty(OutputKeys.METHOD, "xml"); transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); if (prettyPrint) { transformer.setOutputProperty(OutputKeys.INDENT, "yes"); transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4"); } transformer.transform(new DOMSource(doc), new StreamResult(new OutputStreamWriter(out, "UTF-8"))); } }