如何将 org.w3c.dom.Document 对象转换为字符串?

111

我想将一个org.w3c.dom.Document对象转换为字符串。 我正在使用Java 6,并且可以使用任何完全免费的技术来完成任务。 我尝试了这个线程中的解决方案 - 在Java中将XML文档转换为字符串的更加优雅的方法存在吗?,其中他们有:

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

但是遇到了以下可怕的异常...

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)

如果你不想依赖某种序列化器,身份转换(http://en.wikipedia.org/wiki/Identity_transform)是最好的选择。已经给出的两个答案就是这样做的。运行这样一个空的转换就会在后台执行身份转换。 - Pavel Veller
4个回答

105

使用类似以下代码:

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;
    }
} 

21
@MubasharAhmad transformer.setOutputProperty(OutputKeys.INDENT, "yes"); - Guillaume Polet
1
经典的Java。为了完成最简单的任务,需要5个不同的类和一个工厂。 - undefined

100

如果您可以进行转换,可以尝试这样做。

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());

有没有想法如何为上述代码编写JUnits?我在编写相同的代码时遇到了verifyError。我在SO上提出了一个问题,如果您有时间,请回答。https://stackoverflow.com/q/48560458/5989309 - Alan Pallath
2
我不会为这样的代码编写单元测试。你将会测试框架的基础设施而不是你的应用逻辑。检查基础设施是否“正常工作”可以作为集成或端到端测试的一部分。 - Adriaan Koster
5
我希望有一种方法可以避免太多的样板代码。 - bluelurker
我在一些标签中(例如“link”标签)得到了“xmlns”属性。<link href="my.css" rel="stylesheet" type="text/css" xmlns="http://www.w3.org/1999/xhtml">。 有没有什么方法可以避免这种情况? - ankur_rajput

23

这个方法对我有效,如此页面所述:


TransformerFactory tf = TransformerFactory.newInstance();
Transformer trans = tf.newTransformer();
StringWriter sw = new StringWriter();
trans.transform(new DOMSource(document), new StreamResult(sw));
return sw.toString();

1
一份基于Zaz的回答的Scala版本。
  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)
    }
  }

有了这个,你可以执行 doc.toXmlString() 或调用 getStringFromDocument(doc) 函数。


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