java - 如何使用 XPATH 从 XML 中获取值

Question

这是我的 xml，我想获取 ID 标记“4654”的值

<Entity>
       <acc>
            <id>4654</id>
            <name>abc</name>
       </acc>
       <acc>
            <id>5465</id>
            <name>xyz</name>
       </acc>

我正在使用这段代码来检索 Id 值

       DocumentBuilderFactory factory =    DocumentBuilderFactory.newInstance();
       DocumentBuilder builder = factory.newDocumentBuilder();
       Document document = builder.parse(new InputSource(new StringReader(xml))); 
       XPath xPath = XPathFactory.newInstance().newXPath();
       NodeList  node = (NodeList) xPath.evaluate("/Entity/acc/id/text()", document, XPathConstants.NODE);
       System.out.println("node length:"+node.getLength());
       System.out.println("node value:"+ node.item(0).getNodeValue());
       return node.item(0).getNodeValue();

输出返回空

任何帮助将不胜感激

Answer 1

您需要使用 XPathConstants.NODESET 而不是 XPathConstants.NODE

或者您可以将其保留为 XPathConstants.NODE 并将评估更改为返回 Node

Node node = (Node) xPath.evaluate("/Entity/acc/id/text()", document, XPathConstants.NODE);