java - XPath 解析器 java 冗余

Question

所以我需要用 XPath 解析 XML 文件。 一切正常，但如果我有一个标 checkout 现多次，我的代码会显示标签内所有相同标签的所有子标签。 例如:我有一个

<a>
  <b></b>
</a>
<c></c>
<a>
  <b></b>
</a>

输出将是:

a
 b
 b
c
a
 b
 b

我的代码是这样的:

 public void parseFileXPath() throws ParserConfigurationException, IOException, SAXException, XPathExpressionException {
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
    Document doc = documentBuilder.parse(file);
    doc.getDocumentElement().normalize();

    XPathFactory factory = XPathFactory.newInstance();
    XPath xpath = factory.newXPath();

    String expression;
    Node node;
    NodeList nodeList;

    expression="/*";
    node = (Node) xpath.evaluate(expression,doc, XPathConstants.NODE);
    //System.out.println(node.getNodeName());

    expression="/frogans-fsdl/*";
    nodeList = (NodeList) xpath.evaluate(expression,doc, XPathConstants.NODESET);


    NodeList nodeList1;


    for (int i = 0; i < nodeList.getLength(); i++) {
        String aTag = nodeList.item(i).getNodeName();

        System.out.println(aTag);
        expression="/frogans-fsdl/"+aTag+"/*";
        nodeList1 = (NodeList) xpath.evaluate(expression,doc,XPathConstants.NODESET);

        for (int j = 0; j < nodeList1.getLength(); j++) {

            System.out.println("\t"+nodeList1.item(j).getNodeName());
            //TODO
            //Display what's inside each tag
        }

        expression="";
    }



}

请问有什么帮助吗？

Answer 1

以下内部循环代码可能有助于获得您想要的输出:

    NodeList nodeList1;

    for (int i = 0; i < nodeList.getLength(); i++) {
        System.out.println(nodeList.item(i).getNodeName());
        expression="*";
        nodeList1 = (NodeList) xpath.evaluate(expression,nodeList.item(i),XPathConstants.NODESET);
        for (int j = 0; j < nodeList1.getLength(); j++) {
            System.out.println("\t"+nodeList1.item(j).getNodeName());
        }
    }

基本上，您需要将 nodeList.item(i) 作为后续 xpath 评估的第二个参数传递。