解析/读取XML 文件

<?xml version=“1.0”?> <students>     <student>         <name>John</name>         <grade>B</grade>         <age>12</age>     </student>     <student>         <name>Mary</name>         <grade>A</grade>         <age>11</age>     </student>     <student>         <name>Simon</name>         <grade>A</grade>         <age>18</age>     </student> </students> package net.viralpatel.java.xmlparser; import java.io.File; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; public class XMLParser {     public void getAllUserNames(String fileName) {         try {             DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();             DocumentBuilder db = dbf.newDocumentBuilder();             File file = new File(fileName);             if (file.exists()) {                 Document doc = db.parse(file);                 Element docEle = doc.getDocumentElement();                 // Print root element of the document                   System.out.println(“Root element of the document: “                         + docEle.getNodeName());                 NodeList studentList = docEle.getElementsByTagName(“student”);                 // Print total student elements in document                   System.out                         .println(“Total students: “ + studentList.getLength());                 if (studentList != null && studentList.getLength() > 0) {                     for (int i = 0; i < studentList.getLength(); i++) {                         Node node = studentList.item(i);                         if (node.getNodeType() == Node.ELEMENT_NODE) {                             System.out                                     .println(“=====================”);                             Element e = (Element) node;                             NodeList nodeList = e.getElementsByTagName(“name”);                             System.out.println(“Name: “                                     + nodeList.item(0).getChildNodes().item(0)                                             .getNodeValue());                             nodeList = e.getElementsByTagName(“grade”);                             System.out.println(“Grade: “ […]