使用 XPath 选择 XML 节点时如何忽略命名空间
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How to ignore namespace when selecting XML nodes with XPath
提问by lukegf
I have to parse an XML document that looks like this:
我必须解析如下所示的 XML 文档：
<?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>
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.
问题是命名空间“http://oasissta.caiso.com/mrtu-oasis/xsd/OASISReport.xsd”有时可能不同。我想完全忽略它，只从下游标记 MessagePayload 获取我的数据。
The code I am using so far is:
到目前为止我使用的代码是：
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());
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?
如果命名空间永远不会改变，它工作正常，但显然不是这种情况。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？
采纳答案by Dimitre Novatchev
Use:
使用：
/*/*/*/*/*
[local-name()='REPORT_DATA'
or
local-name()='REPORT_HEADER'
]
Anyone care for more complete syntax?
有人关心更完整的语法吗？
String xPathExpression = "/*[local-name()='OASISReport]
/*[local-name()='MessagePayload]
/*[local-name()='RTO]
/*[local-name()='REPORT_ITEM]
/*[local-name()='REPORT_DATA"];
Btw, if the XPath also requires the element index position:
顺便说一句，如果 XPath 还需要元素索引位置：
String xPathExpression = "/*[local-name()='OASISReport][1]
回答by
This is FAQ(but I'm lazy to search duplicates today)
这是常见问题解答（但我今天懒得搜索重复项）
In XPath 1.0
在 XPath 1.0 中
//*[local-name()='name']
Selects any element with "name" as local-name.
选择任何以“name”作为local-name 的元素。
In XPath 2.0 you can use:
在 XPath 2.0 中，您可以使用：
//*:name
