Java DOM4J Parser - Parse XML Document

Langkah-langkah untuk Menggunakan DOM4J

Berikut adalah langkah-langkah yang digunakan saat mengurai dokumen menggunakan DOM4J Parser.

  • Impor paket terkait XML.

  • Buat SAXReader.

  • Buat Dokumen dari file atau aliran.

  • Dapatkan node yang diperlukan menggunakan XPath Expression dengan memanggil document.selectNodes ()

  • Ekstrak elemen root.

  • Iterasi daftar node.

  • Periksa atributnya.

  • Periksa sub-elemen.

Impor paket terkait XML

import java.io.*;
import java.util.*;
import org.dom4j.*;

Buat DocumentBuilder

SAXBuilder saxBuilder = new SAXBuilder();

Buat Dokumen dari file atau aliran

File inputFile = new File("input.txt");
SAXBuilder saxBuilder = new SAXBuilder();
Document document = saxBuilder.build(inputFile);

Ekstrak elemen root

Element classElement = document.getRootElement();

Periksa atributnya

//returns specific attribute
valueOf("@attributeName");

Periksa sub-elemen

//returns first child node
selectSingleNode("subelementName");

Contoh Demo

Berikut adalah file input xml yang perlu kita parse -

<?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>

DOM4JParserDemo.java

package com.tutorialspoint.xml;

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

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

public class DOM4JParserDemo {

   public static void main(String[] args) {

      try {
         File inputFile = new File("input.txt");
         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" );
         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();
      }
   }
}

Ini akan menghasilkan hasil sebagai berikut -

Root element :class
----------------------------

Current Element :student
Student roll no : 
First Name : dinkar
Last Name : kad
First Name : dinkar
Marks : 85

Current Element :student
Student roll no : 
First Name : Vaneet
Last Name : Gupta
First Name : vinni
Marks : 95

Current Element :student
Student roll no : 
First Name : jasvir
Last Name : singn
First Name : jazz
Marks : 90