javax.xml，不会从具有名称空间的XML中提取XPath

答案是您需要正确使用名称空间和名称空间前缀：

首先，

documentBuilderFactory

factory.setNamespaceAware(true);

然后执行此操作以检索所需的值：

XPathFactory xPathfactory = XPathFactory.newInstance();XPath xpath = xPathfactory.newXPath();xpath.setNamespaceContext(new NamespaceContext() {    @Override    public String getNamespaceURI(String prefix) {        if (prefix.equals("soap")) { return "http://www.w3.org/2003/05/soap-envelope";        }        if (prefix.equals("zmb")) { return "urn:zimbra";        }        return XMLConstants.NULL_NS_URI;    }    @Override    public String getPrefix(String namespaceURI) {        throw new UnsupportedOperationException("Not supported yet.");    }    @Override    public Iterator getPrefixes(String namespaceURI) {        throw new UnsupportedOperationException("Not supported yet.");    }});XPathexpression expr =        xpath.compile("/soap:Envelope/soap:Header/zmb:context/zmb:session");String sessionId = (String)expr.evaluate(doc, XPathConstants.STRING);

您可能需要在文件开头添加一行以导入NamespaceContext类：

import javax.xml.namespace.NamespaceContext;

http://ideone.com/X3iX5N