Java XPath编译可以'；具有唯一命名空间的t查询标记

我在这里问了很多问题，但似乎没有什么能解决我所面临的问题

我得到了一个带有唯一名称空间的标记。。就那个标签。我引入了XML名称空间上下文，但我的程序仍然返回0个节点

// Create DocumentBuilderFactory for reading xml file
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();

        factory.setNamespaceAware(true);

        Document doc = builder.parse(new InputSource(new StringReader(text)));

        // Create XPathFactory for creating XPath Object
        XPathFactory xPathFactory = XPathFactory.newInstance();

        // Create XPath object from XPathFactory
        XPath xpath = xPathFactory.newXPath();

        xpath.setNamespaceContext(new NamespaceContext() {
            public String getNamespaceURI(String prefix) {
                if ("cam".equals(prefix))
                    return "urn:xxx:1.0:logging";
                else if ("soapenv".equals(prefix))
                    return "http://schemas.xmlsoap.org/soap/envelope/";
                else if ("xml".equals(prefix))
                    return XMLConstants.XML_NS_URI;
                return XMLConstants.NULL_NS_URI;
            }

            // This method isn't necessary for XPath processing.
            public String getPrefix(String uri) {
                throw new UnsupportedOperationException();
            }

            // This method isn't necessary for XPath processing either.
            public Iterator getPrefixes(String uri) {
                throw new UnsupportedOperationException();
            }
        });

        // Compile the XPath expression for getting the response
         XPathExpression xPathExpr =
         xpath.compile("/cam:message/cam:response/soapenv:Envelope/soapenv:Header/Info[1]/property[@name='response']/text()");


        // XPath text example : executing xpath expression in java
        // Object result = xPathExpr.evaluate(doc, XPathConstants.NODESET);
        // NodeList nodes = (NodeList) result;
        // int length = nodes.getLength();

        String result1 = (String) xPathExpr.evaluate(doc, XPathConstants.STRING);

XML看起来像

 <cam:message xmlns="urn:xxx:1.0:logging">
         <cam:response>
           <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
               <soapenv:Header xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
                   <Info xmlns="urn:xxx:1.0:xxx.core.xxx.Service1">
                      <property name="response">some value</property>
                 </Info>
                 <Info xmlns="urn:xxx:1.0:xxx.core.xxx.Service2">
                      <property name="response">i am interested in this value</property>
                 </Info>
               </soapenv:Header>
           </soapenv:Envelope>
     </cam:response>
</cam:message>

一些价值
我对这个值感兴趣

因此标记

有自己的名称空间。我的程序没有为此返回值。类似地，还有许多信息标签。我对第二个Info标记感兴趣，它的名称空间以Service2结尾

---

请帮助

您当前的XPath表达式只匹配带有否命名空间uri的信息和属性元素

必须将

urn:…Service2

-命名空间添加到

namespacecoxt

内部类：

public String getNamespaceURI(String prefix) {
    if ("cam".equals(prefix))
       // like abvce
    else if ("s2".equals(prefix))
       return "urn:xxx:1.0:xxx.core.xxx.Service2";
    else
       return XMLConstants.NULL_NS_URI;
}

并相应地限定XPath中的

Info

和

属性
步骤，使用前缀
s2
：

xpath.compile("/cam:message/cam:response/soapenv:Envelope/soapenv:Header/s2:Info/s2:property[@name='response']/text()");

除此之外，您的代码和XML文件中还有错误：

a） 在创建DocumentBuilder后，您可以使DocumentBuilderFactory命名空间具有感知性。改为写：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();

<cam:message xmlns:cam="urn:xxx:1.0:logging">
    ....

b） XML使用的前缀
cam
，在根元素中没有正确声明。改为写：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();

<cam:message xmlns:cam="urn:xxx:1.0:logging">
    ....


....
@wero.我做了你建议的更改。。谢谢但我认为这不管用either@Shiv也许你必须进一步调整你的XPath表达式。我对这个XPath是新手。虽然我的路径看起来简单且合乎逻辑，但不知道为什么它不起作用。有什么帮助吗possible@wero.Thank你。在构建器创建之前添加名称空间感知修复了将issue.wrt更改为xml的问题，我对此没有控制权。但这一改变就解决了我的问题。再次谢谢你