为什么我不能为"var“获取节点

Question

有什么原因不能得到"var“节点吗？我没有看到任何打印出来的东西。所以问题是节点什么也不返回。请帮帮忙。非常感谢!

以下是我的java代码：

DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = builder.parse(new InputSource(new StringReader(responseBody)));
XPath xpath = XPathFactory.newInstance().newXPath();
// XPath Query for showing all nodes value
XPathExpression expr = xpath.compile("/vxml/form/var");

NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);
for (int i = 0; i < nodes.getLength(); i++) {
    Node node = nodes.item(i);
    System.out.println("test");
}

以下是xml：

<?xml version="1.0" encoding="UTF-8"?>
<vxml xmlns="http://www.w3.org/2001/vxml" xmlns:voxeo="http://community.voxeo.com/xmlns/vxml" version="2.1">
<form id="XCONTENT">
  <catch event="invalidResponse">
     <assign name="responseRetries" expr="responseRetries+1" />
     <clear namelist="CHOICES" />
     <goto nextitem="CHOICES" />
  </catch>
  <var expr="1" name="responseRetries" />
  <var expr="''" name="choice" />
  <var expr="'8750000'" name="ntfnId" />
  <var expr="'8749000,8748000,8747000,8746000'" name="notIds" />
  <var expr="'228971'" name="deviceId" />
  <var expr="'0'" name="nodeId" />
  <var expr="'1'" name="orgId" />
  <var expr="'English'" name="userPreferredLang" />
  <var expr="'slow'" name="ttsRate" />
  <var expr="false" name="isValidationMessage" />
  <var expr="'8750000'" name="processedNotificationIds" />
  <var expr="'1815f630-bda2-45be-b08b-46a51d3aebd4'" name="callSid" />
  <var expr="'BEFORE'" name="authState" />
  <var expr="''" name="authNotificationIds" />
  <var expr="''" name="nodeName" />
  <var expr="false" name="RESPONSE_PLAYED" />
  <var expr="'true'" name="hasContent" />
   </form>
</vxml>

Answer 1

您的元素位于命名空间中，但是您的XPath正在寻找没有名称空间中的元素。搜索此站点中的"XPath默认命名空间“，以找到其他数千名遇到相同问题的人。