如何将 org.w3c.dom.Document 对象转换为字符串？

Posted 2023-02-26

【中文标题】如何将 org.w3c.dom.Document 对象转换为字符串？

【英文标题】：How do I convert a org.w3c.dom.Document object to a String?

【发布时间】：2012-05-08 12:48:44

【问题描述】：

我想将 org.w3c.dom.Document 对象转换为字符串。我正在使用 Java 6，并且愿意使用任何（完全免费的）能够胜任任务的技术。我尝试了这个线程的解决方案——Is there a more elegant way to convert an XML Document to a String in Java than this code?，他们在那里

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)

如果您不想依赖某种序列化程序，

身份转换 (en.wikipedia.org/wiki/Identity_transform) 是您最好的选择。已经给出的两个答案已经做到了这一点。像这样运行一个空的转换会在幕后进行身份转换。

【参考方案1】：

使用类似的东西

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;
    
 

【讨论】：

@MubasharAhmad transformer.setOutputProperty(OutputKeys.INDENT, "yes");

【参考方案2】：

如果你可以转换，你可以试试这个。

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());

【讨论】：

知道如何为上述代码编写 JUnit 吗？我在写同样的东西时得到了一个verifyError。我在SO中问了一个问题，如果你有空，请回答。 ***.com/q/48560458/5989309

我不会为此类代码编写单元测试。您将测试框架管道而不是应用程序逻辑。检查管道是否“工作”可以作为集成或端到端测试的一部分发生。

我希望有办法避免这么多样板代码。

我在“链接”标签等一些标签中获得了“xmlns”属性。 w3.org/1999/xhtml">。有什么办法可以避免吗？

【参考方案3】：

这对我有用，如 this page 中所述：

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

【参考方案4】：

基于 Zaz 答案的 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)
    
  

这样，您可以执行doc.toXmlString() 或调用getStringFromDocument(doc) 函数。