Woodstox - 当文档没有根时尝试写入 END_DOCUMENT

问题描述

这是我第一次使用 woodstox 编写 XML，但在添加 EndDocument 时出现错误。

我的代码：

private static XMLOutputFactory oF = com.ctc.wstx.stax.WstxOutputFactory.newInstance();
private static XMLInputFactory iF = com.ctc.wstx.stax.WstxInputFactory.newInstance();
iF.setProperty(XMLInputFactory.SUPPORT_DTD,false);
iF.setProperty("javax.xml.stream.isSupportingExternalEntities",false);

protected OutputStream writeXML(InputStream iS) throws XMLStreamException {
  ByteArrayOutputStream oS = new ByteArrayOutputStream();
  try {
    XMLEventWriter eW;

    XMLEventFactory eF = com.ctc.wstx.stax.WstxEventFactory.newInstance();
    eW = oF.createXMLEventWriter(oS);
    eW.add(eF.createStartDocument(););

    XMLEventReader eR = iF.createXMLEventReader(iS);
    while(eR.hasNext()) {
      XMLEvent event = eR.nextEvent();
      if (event.isstartElement()) {
      }
      else if (event.isEndElement()) {
      }
      else if (event.getEventType() != XMLEvent.START_DOCUMENT && event.getEventType() != XMLEvent.END_DOCUMENT) {
        if (event.isstartElement() {
          eW.add(event);
        }
        else if (event.isEndElement()) {
          eW.add(event);
        }
      }
      eR.close();
    }
    eW.add(eF.createEndDocument());
    eW.close();
  }
  catch (Exception e) { e.printstacktrace(); }
  return oS;

}

错误：

javax.xml.stream.XMLStreamException: Trying to write END_DOCUMENT when document has no root (ie. trying to output empty document).
at com.ctc.wstx.sw.BaseStreamWriter.throwOutputError(BaseStreamWriter.java:1589)
at com.ctc.wstx.sw.BaseStreamWriter.reportNwfStructure(BaseStreamWriter.java:1618)
at com.ctc.wstx.sw.BaseStreamWriter._finishDocument(BaseStreamWriter.java:1444)
at com.ctc.wstx.sw.BaseStreamWriter.writeEndDocument(BaseStreamWriter.java:550)
at org.codehaus.stax2.ri.Stax2EventWriterImpl.add(Stax2EventWriterImpl.java:66)

XML 是这样写的：

<?xml version="1.0"?>
  <manifest:manifest xmlns:manifest="a" manifest:version="1.2">
    <manifest:file-entry manifest:full-path="/" manifest:media-type="b.text" manifest:version="1.2"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="c.xml" manifest:media-type=""></manifest:file-entry>
    <manifest:file-entry manifest:full-path="d/" manifest:media-type="e"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="f.png" manifest:media-type="image/png"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="g.xml" manifest:media-type="text/xml"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="h.xml" manifest:media-type="text/xml"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="i.xml" manifest:media-type="text/xml"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="j.rdf" manifest:media-type="application/rdf+xml"></manifest:file-entry>
    <manifest:file-entry manifest:full-path="l.xml" manifest:media-type="text/xml"></manifest:file-entry>

  </manifest:manifest>

我试图禁用验证，将属性 P_OUTPUT_VALIDATE_STRUCTURE、P_OUTPUT_VALIDATE_CONTENT、P_OUTPUT_VALIDATE_NAMES、P_OUTPUT_VALIDATE_ATTR、P_OUTPUT_FIX_CONTENT 设置为 false，但我收到此错误：

javax.xml.stream.XMLStreamException: No open start element,when trying to write end element
at com.ctc.wstx.sw.BaseStreamWriter.throwOutputError(BaseStreamWriter.java:1589)
at com.ctc.wstx.sw.BaseStreamWriter.reportNwfStructure(BaseStreamWriter.java:1618)
at com.ctc.wstx.sw.BaseNsstreamWriter.doWriteEndTag(BaseNsstreamWriter.java:664)
at com.ctc.wstx.sw.BaseNsstreamWriter.writeEndElement(BaseNsstreamWriter.java:291)
at com.ctc.wstx.sw.BaseStreamWriter._finishDocument(BaseStreamWriter.java:1457)
at com.ctc.wstx.sw.BaseStreamWriter.writeEndDocument(BaseStreamWriter.java:550)
at org.codehaus.stax2.ri.Stax2EventWriterImpl.add(Stax2EventWriterImpl.java:66)

禁用 P_AUTOMATIC_END_ELEMENTS，出现第一个错误。

我做错了什么？

解决方法

看起来处理坏了；不知道你为什么有这个：

      if (event.isStartElement()) {
      }
      else if (event.isEndElement()) {
      }

但是这会阻止元素被写入，然后你有空文档......这不是有效的 XML。 我认为这是一个错误，因为上面代码片段之后的 else 分支正在运行，好像开始元素可能会出现（但由于前面的语句而不能）。