Java-XML读取根元素值

这里有一个例子：

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
                DocumentBuilder builder = builderFactory.newDocumentBuilder();
                Document xmlDocument = builder.parse(file);
                XPath xPath = XPathFactory.newInstance().newXPath();
                //System.out.println("*************************");
                String expression = "/JDF";
                NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);

导入java.io.File；
导入javax.xml.parsers.DocumentBuilderFactory；
导入org.w3c.dom.Document；
导入org.w3c.dom.Element；
导入org.w3c.dom.NodeList；
公共班机{
公共静态void main（字符串[]argv）引发异常{
DocumentBuilderFactory工厂=DocumentBuilderFactory.newInstance（）；
工厂设置验证（true）；
factory.setExpandEntityReferences（假）；
Document doc=factory.newDocumentBuilder（）.parse（新文件（“文件名”）；
元素根=空；
NodeList list=doc.getChildNodes（）；
对于（int i=0；i

---

您可以从

root

object

获取属性，请发布一些代码！Document xmlDocument=builder.parse（文件）；Element=xmlDocument.getDocumentElement（）；字符串descriptiveName=element.getAttribute（“descriptiveName”）；与所有技术一样，使用XML时，必须正确掌握基本原理，此链接将有助于纠正此错误。警告：已打开验证，但未设置org.xml.sax.ErrorHandler，这可能不是所需的。解析器将使用默认的ErrorHandler打印前0个错误。请调用setErrorHandler方法来解决此问题。@stacky-1，请参阅上面的注释

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
                DocumentBuilder builder = builderFactory.newDocumentBuilder();
                Document xmlDocument = builder.parse(file);
                XPath xPath = XPathFactory.newInstance().newXPath();
                //System.out.println("*************************");
                String expression = "/JDF";
                NodeList nodeList = (NodeList) xPath.compile(expression).evaluate(xmlDocument, XPathConstants.NODESET);

import java.io.File;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

    public class Main {
      public static void main(String[] argv) throws Exception{
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setValidating(true);

        factory.setExpandEntityReferences(false);

        Document doc = factory.newDocumentBuilder().parse(new File("filename"));

        Element root = null;

        NodeList list = doc.getChildNodes();
        for (int i = 0; i < list.getLength(); i++) {
          if (list.item(i) instanceof Element) {
            root = (Element) list.item(i);
            break;
          }
        }
        root = doc.getDocumentElement();
      }
    }