使用 XPath 选择 XML 节点时如何忽略命名空间 [英] How to ignore namespace when selecting XML nodes with XPath

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本文介绍了使用 XPath 选择 XML 节点时如何忽略命名空间的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我必须解析一个如下所示的 XML 文档:

I have to parse an XML document that looks like this:

 <?xml version="1.0" encoding="UTF-8" ?> 
 <m:OASISReport xmlns:m="http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd" 
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd">
  <m:MessagePayload>
   <m:RTO>
    <m:name>CAISO</m:name> 
    <m:REPORT_ITEM>
     <m:REPORT_HEADER>
      <m:SYSTEM>OASIS</m:SYSTEM> 
      <m:TZ>PPT</m:TZ> 
      <m:REPORT>AS_RESULTS</m:REPORT> 
      <m:MKT_TYPE>HASP</m:MKT_TYPE> 
      <m:UOM>MW</m:UOM> 
      <m:INTERVAL>ENDING</m:INTERVAL> 
      <m:SEC_PER_INTERVAL>3600</m:SEC_PER_INTERVAL> 
     </m:REPORT_HEADER>
     <m:REPORT_DATA>
      <m:DATA_ITEM>NS_PROC_MW</m:DATA_ITEM> 
      <m:RESOURCE_NAME>AS_SP26_EXP</m:RESOURCE_NAME> 
      <m:OPR_DATE>2010-11-17</m:OPR_DATE> 
      <m:INTERVAL_NUM>1</m:INTERVAL_NUM> 
      <m:VALUE>0</m:VALUE> 
     </m:REPORT_DATA>

问题在于命名空间http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd"有时可能不同.我想完全忽略它,只从下游标签 MessagePayload 获取我的数据.

The problem is that the namespace "http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd" can sometimes be different. I want to ignore it completely and just get my data from tag MessagePayload downstream.

目前我使用的代码是:

String[] namespaces = new String[1];
  String[] namespaceAliases = new String[1];

  namespaceAliases[0] = "ns0";
  namespaces[0] = "http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd";

  File inputFile = new File(inputFileName);

  Map namespaceURIs = new HashMap();

  // This query will return all of the ASR records.
  String xPathExpression = "/ns0:OASISReport
                             /ns0:MessagePayload
                              /ns0:RTO
                               /ns0:REPORT_ITEM
                                /ns0:REPORT_DATA";
  xPathExpression += "|/ns0:OASISReport
                        /ns0:MessagePayload
                         /ns0:RTO
                          /ns0:REPORT_ITEM
                           /ns0:REPORT_HEADER";

  // Load up the raw XML file. The parameters ignore whitespace and other
  // nonsense,
  // reduces DOM tree size.
  SAXReader reader = new SAXReader();
  reader.setStripWhitespaceText(true);
  reader.setMergeAdjacentText(true);
  Document inputDocument = reader.read(inputFile);

  // Relate the aliases with the namespaces
  if (namespaceAliases != null && namespaces != null)
  {
   for (int i = 0; i < namespaceAliases.length; i++)
   {
    namespaceURIs.put(namespaceAliases[i], namespaces[i]);
   }
  }

  // Cache the expression using the supplied namespaces.
  XPath xPath = DocumentHelper.createXPath(xPathExpression);
  xPath.setNamespaceURIs(namespaceURIs);

  List asResultsNodes = xPath.selectNodes(inputDocument.getRootElement());

如果命名空间从不改变,它工作正常,但显然情况并非如此.我需要做什么才能让它忽略命名空间?或者,如果我知道所有可能的命名空间值的集合,我如何将它们全部传递给 XPath 实例?

It works fine if the namespace never changes but that is obviously not the case. What do I need to do to make it ignore the namespace? Or if I know the set of all possible namespace values, how can I pass them all to the XPath instance?

推荐答案

使用:

/*/*/*/*/*
        [local-name()='REPORT_DATA' 
       or 
         local-name()='REPORT_HEADER'
        ]

这篇关于使用 XPath 选择 XML 节点时如何忽略命名空间的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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