java - 带有重复标签的 XPath 和 Java

Question

我在用 Java 解析 XML 文件时遇到一些问题。该文件采用以下形式:

<root>
  <thing>
    <name>Thing1</name>
    <property>
      <name>Property1</name>
    </property>
    ...
  </thing>
  ...
</root>

最终，我想将此文件转换为 Thing 对象列表，该列表将具有字符串名称 (Thing1) 和 Property 对象列表，每个对象也将具有名称 (Property1)。

我一直在尝试使用 xpaths 来获取这些数据，但是当我尝试仅获取“事物”的名称时，它会为我提供“事物”中出现的所有名称，包括“属性”的名称。我的代码是:

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document dom = db.parse(filename);
XPath xpath = XPathFactory.newInstance().newXPath();


XPathExpression thingExpr = xpath.compile("//thing");
NodeList things = (NodeList)thingExpr.evaluate(dom, XPathConstants.NODESET);
for(int count = 0; count < things.getLength(); count++)
{
    Element thing = (Element)things.item(count);
    XPathExpression nameExpr = xpath.compile(".//name/text()");
    NodeList name = (NodeList) nameExpr.evaluate(thing, XPathConstants.NODESET);
    for(int i = 0; i < name.getLength(); i++)
    {
        System.out.println(name.item(i).getNodeValue());    
    }
}

有人可以帮忙吗？提前致谢!

Answer 1

你可以尝试类似...

public class TestXPath {

    public static void main(String[] args) {
        String xml =
                        "<root>\n"
                        + "    <thing>\n"
                        + "        <name>Thing1</name>\n"
                        + "        <property>\n"
                        + "            <name>Property1</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property2</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property3</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property4</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property5</name>\n"
                        + "        </property>\n"
                        + "    </thing>/n"
                        + "    <NoAThin>\n"
                        + "        <name>Thing2</name>\n"
                        + "        <property>\n"
                        + "            <name>Property1</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property2</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property3</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property4</name>\n"
                        + "        </property>\n"
                        + "        <property>\n"
                        + "            <name>Property5</name>\n"
                        + "        </property>\n"
                        + "    </NoAThin>/n"
                        + "</root>";

        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            ByteArrayInputStream bais = new ByteArrayInputStream(xml.getBytes());
            Document dom = db.parse(bais);
            XPath xpath = XPathFactory.newInstance().newXPath();

            // Find the "thing" node...
            XPathExpression thingExpr = xpath.compile("/root/thing");
            NodeList things = (NodeList) thingExpr.evaluate(dom, XPathConstants.NODESET);

            System.out.println("Found " + things.getLength() + " thing nodes...");

            // Find the property nodes of thing
            XPathExpression expr = xpath.compile("property");
            NodeList nodes = (NodeList) expr.evaluate(things.item(0), XPathConstants.NODESET);

            System.out.println("Found " + nodes.getLength() + " thing/property nodes...");

            // Find all the property "name" nodes under thing
            expr = xpath.compile("property/name");
            nodes = (NodeList) expr.evaluate(things.item(0), XPathConstants.NODESET);

            System.out.println("Found " + nodes.getLength() + " name nodes...");
            System.out.println("Property value = " + nodes.item(0).getTextContent());

            // Find all nodes that have property nodes
            XPathExpression exprAll = xpath.compile("/root/*/property");
            NodeList nodesAll = (NodeList) exprAll.evaluate(dom, XPathConstants.NODESET);
            System.out.println("Found " + nodesAll.getLength() + " property nodes...");

        } catch (Exception exp) {
            exp.printStackTrace();
        }
    }
}

这会给你类似的输出

Found 1 thing nodes...
Found 5 thing/property nodes...
Found 5 name nodes...
Property value = Property1
Found 10 property nodes...