java使用DOM操作XML

XML DOM简介

XML DOM 是用于获取、更改、添加或删除 XML 元素的标准。
XML 文档中的每个成分都是一个节点。

• DOM 是这样规定的&＃xff1a;

整个文档是一个文档节点
每个 XML 标签是一个元素节点
包含在 XML 元素中的文本是文本节点
每一个 XML 属性是一个属性节点
注释属于注释节点

元素节点不包括文本&＃xff0c;元素节点的文本是存储在文本节点中的。

XML 文档的 documentElement 属性是根节点。

在jdk中&＃xff0c;Document接口继承自Node接口
Element接口也继承自Node接口

DOM方式读取XML文件

项目目录结构图&＃xff1a;

config包下language.xml文件


<languages cat &＃61; "it"><lan id &＃61; "1"><name>javaname><ide>Eclipseide>lan><lan id &＃61; "2"><name>swiftname><ide>XCodeide>lan><lan id &＃61; "3"><name>C#name><ide>Visual Studioide>lan>
languages>

ReadXML.java

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 ReadXML {public static void main(String[] args) {try {DocumentBuilderFactory factory &＃61; DocumentBuilderFactory.newInstance();DocumentBuilder builder &＃61; factory.newDocumentBuilder(); Document document &＃61; builder.parse(new File("src/config/language.xml"));//解析文档Element root &＃61; document.getDocumentElement(); //获取根节点System.out.println("language&＃61;" &＃43; root.getAttribute("cat"));System.out.println("-------------");NodeList list &＃61; root.getElementsByTagName("lan");//获取根节点的标签名为“lan”的子节点for (int i &＃61; 0; i //遍历得到每个"lan"节点System.out.println(lan.getTagName()&＃43; "&＃61;" &＃43; lan.getAttribute("id"));NodeList lanList &＃61; lan.getChildNodes(); //获取“lan”节点的子节点for (int j &＃61; 0; j if (node instanceof Element) {System.out.println(node.getNodeName()&＃43;"&＃61;"&＃43;node.getTextContent());}}System.out.println("*****************");}} catch (Exception e) {e.printStackTrace();}}
}


控制台输出如下&＃xff1a;

language&＃61;it
-------------
lan&＃61;1
name&＃61;java
ide&＃61;Eclipse
*****************
lan&＃61;2
name&＃61;swift
ide&＃61;XCode
*****************
lan&＃61;3
name&＃61;C#
ide&＃61;Visual Studio
*****************

DOM方式创建XML文件

项目结构图如下&＃xff1a;

&＃xfffc;
CreateXML.java文件

import java.io.File;
import java.io.StringWriter;import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;import org.w3c.dom.Document;
import org.w3c.dom.Element;public class CreateXML {public static void main(String[] args) {try {DocumentBuilderFactory factory &＃61; DocumentBuilderFactory.newInstance();DocumentBuilder builder &＃61; factory.newDocumentBuilder();Document document &＃61; builder.newDocument();Element languages &＃61; document.createElement("languages");languages.setAttribute("cat", "it");Element lan_1 &＃61; document.createElement("lan");lan_1.setAttribute("id", "1");Element name_1 &＃61; document.createElement("name");name_1.setTextContent("Java");Element ide_1 &＃61; document.createElement("ide");ide_1.setTextContent("Eclipse");lan_1.appendChild(name_1);lan_1.appendChild(ide_1);languages.appendChild(lan_1);document.appendChild(languages);//将构建好的xml输出TransformerFactory transformerFactory &＃61; TransformerFactory.newInstance();Transformer transformer &＃61; transformerFactory.newTransformer();//输出到控制台StringWriter writer &＃61; new StringWriter();transformer.transform(new DOMSource(document), new StreamResult(writer));System.out.println(writer.toString());//输出到文件transformer.transform(new DOMSource(document), new StreamResult(new File("language.xml")));} catch (ParserConfigurationException e) {e.printStackTrace();} catch (TransformerConfigurationException e) {e.printStackTrace();} catch (TransformerException e) {e.printStackTrace();}}
}

控制台输出如下&＃xff1a;

<languages cat&＃61;"it"><lan id&＃61;"1"><name>Javaname><ide>Eclipseide>lan>languages>

运行之后刷新项目目录&＃xff0c;可看到已经产生language.xml文件&＃xff1a;

&＃xfffc;
language.xml文件&＃xff1a;


<languages cat&＃61;"it"><lan id&＃61;"1"><name>Javaname><ide>Eclipseide>lan>
languages>