¿Cómo convierto un objeto org.w3c.dom.Document en una Cadena?

Question

Quiero convertir un objeto org.w3c.dom.Document en una Cadena. Estoy usando Java 6 y estoy abierto a usar cualquier tecnología (completamente gratuita) que esté a la altura de la tarea. Probé la solución de este hilo - Is there a more elegant way to convert an XML Document to a String in Java than this code?, donde tienen

DOMImplementationLS domImplementation = (DOMImplementationLS) doc.getImplementation(); 
LSSerializer lsSerializer = domImplementation.createLSSerializer(); 
String html = lsSerializer.writeToString(doc); 

pero fue recibido con la siguiente excepción horrendo ...

org.w3c.dom.DOMException: DOM method not supported 
    at org.w3c.tidy.DOMDocumentImpl.getImplementation(DOMDocumentImpl.java:129) 
    at com.myco.myproj.cleaners.JTidyCleaner.outputDocAsString(JTidyCleaner.java:74) 
    at com.myco.myproj.cleaners.JTidyCleaner.parse(JTidyCleaner.java:63) 
    at com.myco.myproj.util.NetUtilities.getUrlAsDocument(NetUtilities.java:51) 
    at com.myco.myproj.parsers.AbstractHTMLParser.getEventFromElement(AbstractHTMLParser.java:131) 
    at com.myco.myproj.parsers.AbstractHTMLParser.parsePage(AbstractHTMLParser.java:100) 
    at com.myco.myproj.parsers.AbstractHTMLParser.getEvents(AbstractHTMLParser.java:63) 
    at com.myco.myproj.domain.EventFeed.refresh(EventFeed.java:87) 
    at com.myco.myproj.domain.EventFeed.getEvents(EventFeed.java:72) 
    at com.myco.myproj.parsers.impl.ChicagoCouncilGlobalAffairsParserTest.testParser(ChicagoCouncilGlobalAffairsParserTest.java:21) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) 
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) 
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) 
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) 
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28) 
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) 
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83) 
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) 
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231) 
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) 
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) 
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) 
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) 
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) 
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) 
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) 
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) 
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236) 
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) 
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) 
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) 
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) 

Answer 1

Si está bien hacer la transformación, puedes probar esto.

DocumentBuilderFactory domFact = DocumentBuilderFactory.newInstance(); 
DocumentBuilder builder = domFact.newDocumentBuilder(); 
Document doc = builder.parse(st); 
DOMSource domSource = new DOMSource(doc); 
StringWriter writer = new StringWriter(); 
StreamResult result = new StreamResult(writer); 
TransformerFactory tf = TransformerFactory.newInstance(); 
Transformer transformer = tf.newTransformer(); 
transformer.transform(domSource, result); 
System.out.println("XML IN String format is: \n" + writer.toString()); 

Answer 2

uso algo como

import java.io.*; 
import javax.xml.transform.*; 
import javax.xml.transform.dom.*; 
import javax.xml.transform.stream.*; 

//method to convert Document to String 
public String getStringFromDocument(Document doc) 
{ 
    try 
    { 
     DOMSource domSource = new DOMSource(doc); 
     StringWriter writer = new StringWriter(); 
     StreamResult result = new StreamResult(writer); 
     TransformerFactory tf = TransformerFactory.newInstance(); 
     Transformer transformer = tf.newTransformer(); 
     transformer.transform(domSource, result); 
     return writer.toString(); 
    } 
    catch(TransformerException ex) 
    { 
     ex.printStackTrace(); 
     return null; 
    } 
} 

Answer 3

Una versión de Scala basada en la respuesta de Zaz.

case class DocumentEx(document: Document) { 
    def toXmlString(pretty: Boolean = false):Try[String] = { 
     getStringFromDocument(document, pretty) 
    } 
    } 

    implicit def documentToDocumentEx(document: Document):DocumentEx = { 
    DocumentEx(document) 
    } 

    def getStringFromDocument(doc: Document, pretty:Boolean): Try[String] = { 
    try 
    { 
     val domSource= new DOMSource(doc) 
     val writer = new StringWriter() 
     val result = new StreamResult(writer) 
     val tf = TransformerFactory.newInstance() 
     val transformer = tf.newTransformer() 
     if (pretty) 
     transformer.setOutputProperty(OutputKeys.INDENT, "yes") 
     transformer.transform(domSource, result) 
     Success(writer.toString); 
    } 
    catch { 
     case ex: TransformerException => 
     Failure(ex) 
    } 
    } 

Con esto, se puede hacer ya sea doc.toXmlString() o llamar a la función getStringFromDocument(doc).