java如何解析/读取xml文件

本文实例为大家分享了java解析/读取xml文件的方法，供大家参考，具体内容如下

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:

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);
    }
  }
  public static void main(String[] args) {  

    XMLParser parser = new XMLParser();
    parser.getAllUserNames("c:\\test.xml");
  }
} 

以上就是本文的全部内容，希望对大家的学习有所帮助。