Converting DOM Document to File

Issue: BAEL-2167

xml/src/main/java/com/baeldung/xml/XMLDocumentWriter.java

@@ -0,0 +1,41 @@
+package com.baeldung.xml;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+
+import javax.xml.transform.OutputKeys;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerConfigurationException;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+
+import org.w3c.dom.Document;
+
+public class XMLDocumentWriter {
+    
+    public void write(Document document, String fileName, boolean excludeDeclaration, boolean prettyPrint) {
+        try(FileWriter writer = new FileWriter(new File(fileName))) {
+            TransformerFactory transformerFactory = TransformerFactory.newInstance();
+            Transformer transformer = transformerFactory.newTransformer();
+            if(excludeDeclaration) {
+                transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
+            }
+            if(prettyPrint) {
+                transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+                transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
+            }
+            DOMSource source = new DOMSource(document);
+            StreamResult result = new StreamResult(writer);
+            transformer.transform(source, result);
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        } catch (TransformerConfigurationException e) {
+            throw new IllegalStateException(e);
+        } catch (TransformerException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+}

xml/src/test/java/com/baeldung/xml/XMLDocumentWriterUnitTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.xml;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+
+import org.apache.commons.io.FileUtils;
+import org.junit.After;
+import org.junit.Test;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+import java.io.File;
+
+public class XMLDocumentWriterUnitTest {
+
+    @Test
+    public void givenXMLDocumentWhenWriteIsCalledThenXMLIsWrittenToFile() throws Exception {
+        Document document = createSampleDocument();
+        new XMLDocumentWriter().write(document, "company_simple.xml", false, false);
+    }
+
+    @Test
+    public void givenXMLDocumentWhenWriteIsCalledWithPrettyPrintThenFormattedXMLIsWrittenToFile() throws Exception {
+        Document document = createSampleDocument();
+        new XMLDocumentWriter().write(document, "company_prettyprinted.xml", false, true);
+    }
+
+    private Document createSampleDocument() throws ParserConfigurationException {
+        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
+        DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
+        Document document = documentBuilder.newDocument();
+        Element companyElement = document.createElement("Company");
+        document.appendChild(companyElement);
+        Element departmentElement = document.createElement("Department");
+        departmentElement.setAttribute("name", "Sales");
+        companyElement.appendChild(departmentElement);
+        Element employee1 = document.createElement("Employee");
+        employee1.setAttribute("name", "John Smith");
+        departmentElement.appendChild(employee1);
+        Element employee2 = document.createElement("Employee");
+        employee2.setAttribute("name", "Tim Dellor");
+        departmentElement.appendChild(employee2);
+        return document;
+    }
+
+    @After
+    public void cleanUp() throws Exception {
+        FileUtils.deleteQuietly(new File("company_simple.xml"));
+        FileUtils.deleteQuietly(new File("company_prettyprinted.xml"));
+    }
+}