Java DOM4J解析器 查询XML文档

Java DOM4J解析器 查询XML文档的示例

需要解析的文件input.xml

<?xml version = "1.0"?>
<class>
    <student rollno = "393">
        <firstname>dinkar</firstname>
        <lastname>kad</lastname>
        <nickname>dinkar</nickname>
        <marks>85</marks>
    </student>

    <student rollno = "493">
        <firstname>Vaneet</firstname>
        <lastname>Gupta</lastname>
        <nickname>vinni</nickname>
        <marks>95</marks>
    </student>

    <student rollno = "593">
        <firstname>jasvir</firstname>
        <lastname>singn</lastname>
        <nickname>jazz</nickname>
        <marks>90</marks>
    </student>
</class>

编写Java DOM4J解析器 查询XML文档的程序

package com.yiidian;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.util.List;

public class DOM4JQueryDemo {

   public static void main(String[] args) {

      try {
         File inputFile = new File("input.xml");
         SAXReader reader = new SAXReader();
         Document document = reader.read( inputFile );

         System.out.println("Root element :" + document.getRootElement().getName());

         Element classElement = document.getRootElement();

         List<Node> nodes = document.selectNodes("/class/student[@rollno = '493']" );
         System.out.println("----------------------------");
         
         for (Node node : nodes) {
            System.out.println("\nCurrent Element :" 
               + node.getName());
            System.out.println("Student roll no : " 
               + node.valueOf("@rollno") );
            System.out.println("First Name : "
               + node.selectSingleNode("firstname").getText());
            System.out.println("Last Name : "
               + node.selectSingleNode("lastname").getText());
            System.out.println("First Name : "
               + node.selectSingleNode("nickname").getText());
            System.out.println("Marks : "
               + node.selectSingleNode("marks").getText());
         }
      } catch (DocumentException e) {
         e.printStackTrace();
      }
   }
}

输出结果为：