Java中用于获取XPath元素的xml表达式

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;

public class XPathExample {
    public static void main(String[] args) throws Exception {
        // 加载XML文档
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse("path/to/xml/file.xml");

        // 创建XPath对象
        XPathFactory xpathFactory = XPathFactory.newInstance();
        XPath xpath = xpathFactory.newXPath();

        // 编译XPath表达式
        XPathExpression expr = xpath.compile("//elementName");

        // 执行XPath表达式并获取结果
        NodeList nodes = (NodeList) expr.evaluate(document, XPathConstants.NODESET);

        // 遍历结果
        for (int i = 0; i < nodes.getLength(); i++) {
            System.out.println(nodes.item(i).getNodeName());
        }
    }
}