Java中分析和读取xml文件范例

Java中分析和读取xml文件范例，非常实用的代码

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>

Java代码分析上面的xml文件

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: "
                                    + 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);
        }
    }
    // http://www.75271.com
    public static void main(String[] args) {
 
        XMLParser parser = new XMLParser();
        parser.getAllUserNames("c:\\test.xml");
    }
}