Java 从XML文件中读取值

我知道如何使用

getelementbyTag

读取Java中的简单XML文件，但我想从这里读取MAC地址，即Java中的01-0C-CD-01-00-34

我试图使用

getElementsByTagName（“”）

，但是我应该传递什么参数来获取具有

type=“MAC Address”

的元素

010C-CD-01-00-34
000
4
0001

我目前的代码是：

public static void main(String argv[]) {
    try {
        File fXmlFile = new File("C:\\Users\\User\\Desktop\\Temp\\ReadXml\\staff.xml");
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(fXmlFile);

        doc.getDocumentElement().normalize();

        NodeList nList = doc.getElementsByTagName("Address");

        for (int temp = 0; temp < nList.getLength(); temp++) {
            Node nNode = nList.item(temp);

            if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                Element eElement = (Element) nNode;
                System.out.println("MAC: " + eElement.getElementsByTagName("").item(0).getTextContent());
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}

publicstaticvoidmain（字符串argv[]）{
试一试{
File fXmlFile=新文件（“C:\\Users\\User\\Desktop\\Temp\\ReadXml\\staff.xml”）；
DocumentBuilderFactory dbFactory=DocumentBuilderFactory.newInstance（）；
DocumentBuilder dBuilder=dbFactory.newDocumentBuilder（）；
documentdoc=dBuilder.parse（fXmlFile）；
doc.getDocumentElement（）.normalize（）；
NodeList nList=doc.getElementsByTagName（“地址”）；
对于（int-temp=0；temp

您可以使用xpath查找xml文档的特定部分

        File fXmlFile = new File("C:\\Users\\User\\Desktop\\Temp\\ReadXml\\staff.xml");
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(fXmlFile);

        // Create XPathExpression
        XPathFactory xpathFactory = XPathFactory.newInstance();
        XPath xpath = xpathFactory.newXPath();
        XPathExpression expr =
                xpath.compile("/Address/P[@type='MAC-Address']/text()");
        // evaluate the Xpath and return result as a string.
        String mac = (String) expr.evaluate(doc, XPathConstants.STRING);

        System.out.println("MAC: " + mac);

Xpath类都来自

java.xml.Xpath

包

import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;

如果要导航节点，可以。您不需要规范化文档，但在查找节点时，确实需要使用document元素，而不仅仅是doc。你可以得到所有的“P”标签并查找MAC地址。比如：

        NodeList nList = doc.getDocumentElement().getElementsByTagName("P");

        for (int temp = 0; temp < nList.getLength(); temp++) {
            Node nNode = nList.item(temp);

            if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                Element eElement = (Element) nNode;
                if ("MAC-Address".equals(eElement.getAttribute("type"))) {
                    System.out.println("MAC: " + eElement.getTextContent());
                }
            }
        }

NodeList nList=doc.getDocumentElement（）.getElementsByTagName（“P”）；
对于（int-temp=0；temp

        NodeList nList = doc.getDocumentElement().getElementsByTagName("P");

        for (int temp = 0; temp < nList.getLength(); temp++) {
            Node nNode = nList.item(temp);

            if (nNode.getNodeType() == Node.ELEMENT_NODE) {
                Element eElement = (Element) nNode;
                if ("MAC-Address".equals(eElement.getAttribute("type"))) {
                    System.out.println("MAC: " + eElement.getTextContent());
                }
            }
        }