Java DOM解析器 - 解析XML文檔

使用DOM的步驟

以下是在使用DOM解析器解析文檔使用的步驟。

• 導入XML相關的軟件包。

• 創建DocumentBuilder

• 從文件或流創建一個文檔

• 提取根元素

• 檢查屬性

• 檢查子元素

導入XML相關的軟件包

import org.w3c.dom.*; import javax.xml.parsers.*; import java.io.*;

創建 DocumentBuilder

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder();

從文件或流創建一個文檔

StringBuilder xmlStringBuilder = new StringBuilder(); xmlStringBuilder.append(" "); ByteArrayInputStream input = new ByteArrayInputStream( xmlStringBuilder.toString().getBytes("UTF-8")); Document doc = builder.parse(input);

提取根元素

Element root = document.getDocumentElement();

檢查屬性

//returns specific attribute getAttribute("attributeName"); //returns a Map (table) of names/values getAttributes();

檢查子元素

//returns a list of subelements of specified name getElementsByTagName("subelementName"); //returns a list of all child nodes getChildNodes();

演示示例

這是輸入需要解析的 xml 文件：

dinkar kad dinkar 85 Vaneet Gupta vinni 95 jasvir singn jazz 90

演示示例：

DomParserDemo.java

package com.yiibai.xml; import java.io.File; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.DocumentBuilder; import org.w3c.dom.Document; import org.w3c.dom.NodeList; import org.w3c.dom.Node; import org.w3c.dom.Element; public class DomParserDemo { public static void main(String[] args){ try { File inputFile = new File("input.txt"); DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder dBuilder = dbFactory.newDocumentBuilder(); Document doc = dBuilder.parse(inputFile); doc.getDocumentElement().normalize(); System.out.println("Root element :" + doc.getDocumentElement().getNodeName()); NodeList nList = doc.getElementsByTagName("student"); System.out.println("----------------------------"); for (int temp = 0; temp < nList.getLength(); temp++) { Node nNode = nList.item(temp); System.out.println("\nCurrent Element :" + nNode.getNodeName()); if (nNode.getNodeType() == Node.ELEMENT_NODE) { Element eElement = (Element) nNode; System.out.println("Student roll no : " + eElement.getAttribute("rollno")); System.out.println("First Name : " + eElement .getElementsByTagName("firstname") .item(0) .getTextContent()); System.out.println("Last Name : " + eElement .getElementsByTagName("lastname") .item(0) .getTextContent()); System.out.println("Nick Name : " + eElement .getElementsByTagName("nickname") .item(0) .getTextContent()); System.out.println("Marks : " + eElement .getElementsByTagName("marks") .item(0) .getTextContent()); } } } catch (Exception e) { e.printStackTrace(); } } }

這將產生以下結果：

Root element :class

Current Element :student
Student roll no : 393
First Name : dinkar
Last Name : kad
Nick Name : dinkar
Marks : 85

Current Element :student
Student roll no : 493
First Name : Vaneet
Last Name : Gupta
Nick Name : vinni
Marks : 95

Current Element :student
Student roll no : 593
First Name : jasvir
Last Name : singn
Nick Name : jazz
Marks : 90