<?xml version="1.0" encoding="UTF-8"?>
<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>

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: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());
                            nodeList = e.getElementsByTagName("age");
                            System.out.println("Age: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());
                        }
                    }
                } else {
                    System.exit(1);
                }
            }
        } catch (Exception e) {
            System.out.println(e);
        }
    }
    public static void main(String[] args) {
        XMLParser parser = new XMLParser();
        String path = System.getProperty("user.dir");
        //读取C盘的xml文件
        parser.getAllUserNames("c:\\test.xml");
        // 在当前的项目跟目录下新建个students.xml
        String finalPath = path + "\\" + "src" + "\\" + "students.xml";
        System.out.println(finalPath);
        parser.getAllUserNames(finalPath);
    }
}