一、前言
Jdom是什么?
Jdom是一个开源项目,基于树形结构,利用纯java的技术对XML文档实现解析,生成,序列化以及多种操作。它是直接为java编程服务,利用java语言的特性(方法重载,集合),把SAX和DOM的功能结合起来,尽可能的把原来解析xml变得简单,我们使用Jdom解析xml会是一件轻松的事情。
Jdom的优点:
1、Jdom专用于java技术,比Dom应用占用更少内存。
2、Jdom提供更加简单和逻辑性访问xml信息的基础方法
3、除xml文件外,Jdom还可以访问其他的数据源,例如可以创建类从SQL查询结果中访问数据
Jdom的构成:
Jdom由6个包构成
Element类表示XML文档的元素
org.jdom: 解析xml文件所要用到的基础类
org.jdom.adapters: 包含DOM适配的Java类
org.jdom.filter: 包含xml文档的过滤类
org.jdom.input: 包含读取XML文档的Java类
org.jdom.output: 包含输出XML文档的类
org.jdom.trans form: 包含将Jdom xml文档接口转换为其他XML文档接口的Java类
xml是什么?
xml是一种广为使用的可扩展标记语言,java中解析xml的方式有很多,最常用的像jdom、dom4j、sax等等。
Jdom包下载:http://www.jdom.org/downloads/index.html
这里笔者代码做的是使用java创建一个xml和读取一个xml,仅作为笔记介绍。
二、操作
下载jdom包,解压文件jdom-2.0.6.jar,jdom-2.0.6-javadoc.jar,将包导入到lib文件夹下。(注,如果有错误的话,将Jdom中的包全部导入)
例子1:使用jdom创建一个xml文件,名字为people.xml
新建类CareateJdom
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package com.book.jdom; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import org.jdom2.Document; import org.jdom2.Element; import org.jdom2.output.Format; import org.jdom2.output.XMLOutputter; //生成xml文件 public class CreateJdom { public static void main(String[] args) { //定义元素 Element people,student; people = new Element( "people" ); student = new Element( "student" ); //设置属性 student.setAttribute( "name" , "张三" ); student.setAttribute( "salary" , "8000" ); //设置文本 student.setText( "呵呵" ); //将其添加到根目录下 people.addContent(student); //新建一个文档。 Document doc = new Document(people); //读取格式,赋值给当前的Format Format format = Format.getCompactFormat(); //对当前格式进行初始化 format.setEncoding( "UTF-8" ); //设置xml文件缩进4个空格 format.setIndent( " " ); //建一个xml输出工厂,将格式给工厂 XMLOutputter xmlout = new XMLOutputter(format); try { //将其写好的文本给工厂,并且建一个文件输出流,将数据输出 xmlout.output(doc, new FileOutputStream( "people.xml" )); System.out.println( "成功!" ); } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } /*运行结果: <?xml version="1.0" encoding="UTF-8"?> <people> <student name="张三" salary="8000" /> </people> * */ |
例子2:使用Jdom解析people.xml文件
新建Readxml类
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package com.book.jdom; import java.io.IOException; import java.util.List; import org.jdom2.Document; import org.jdom2.Element; import org.jdom2.JDOMException; import org.jdom2.input.SAXBuilder; //读取people.xml文档 public class Readxml { public static void main(String[] args) { //新建构造器解析xml SAXBuilder sax = new SAXBuilder(); //建一个文档去接受数据 Document doc; try { //获取people.xml文档 doc = sax.build( "people.xml" ); //获得根节点 Element people = doc.getRootElement(); //获得根节点下的节点数据 List<Element> list = people.getChildren(); for ( int i = 0 ;i<list.size();i++){ Element e = list.get(i); //获得属性值 System.out.println( "name:" +e.getAttributeValue( "name" )+ " salary:" +e.getAttributeValue( "salary" )); //获得文本值 System.out.println(e.getText()); } } catch (JDOMException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } /* * 运行结果: * name:张三 salary:8000 呵呵 * */ |
解析xml
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用jdom获取多个相同标签名的不同属性值的方法 <?xml version= "1.0" encoding= "UTF-8" ?> <Configuration> <Key Name= "China" > <Value Name= "TextKey" >China</Value> <Value Name= "Enabled" > true </Value> <Value Name= "PhotoIDWidth" >38PhotoIDWidth</Value> <Value Name= "PhotoIDHeight" >38</Value> <Key Name= "Adult" > <Value Name= "CrownPercent" >0.10</Value> <Value Name= "HeadPercent" >0.60AdultHeadPercent</Value> </Key> <Key Name= "Child" > <Value Name= "CrownPercent" >0.10</Value> <Value Name= "HeadPercent" >0.60ChildHeadPercent</Value> </Key> </Key> <Key Name= "Australia" > <Value Name= "TextKey" >Australia</Value> <Value Name= "Enabled" > true </Value> <Value Name= "PhotoIDWidth" >35PhotoIDWidth</Value> <Value Name= "PhotoIDHeight" >45</Value> <Key Name= "Adult" > <Value Name= "CrownPercent" >0.061</Value> <Value Name= "HeadPercent" >0.756 "Adult" HeadPercent</Value> </Key> <Key Name= "Child" > <Value Name= "CrownPercent" >0.072</Value> <Value Name= "HeadPercent" >0.711ChildHeadPercent</Value> </Key> </Key> <Key Name= "Austria" > <Value Name= "TextKey" >Austria</Value> <Value Name= "Enabled" > true </Value> <Value Name= "PhotoIDWidth" >35PhotoIDWidth</Value> <Value Name= "PhotoIDHeight" >45</Value> <Key Name= "Adult" > <Value Name= "CrownPercent" >0.064</Value> <Value Name= "HeadPercent" >0.744AdultHeadPercent</Value> </Key> <Key Name= "Child" > <Value Name= "CrownPercent" >0.078</Value> <Value Name= "HeadPercent" >0.689ChildHeadPercent</Value> </Key> </Key> </Configuration> package input; import java.io.IOException; import java.util.ArrayList; import java.util.List; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; public class ReadXML { /** * @param args */ public static void main(String[] args) throws JDOMException, IOException { SAXBuilder sb = new SAXBuilder(); //构造文档对象 Document doc = sb.build(Test.class.getClassLoader().getResourceAsStream( "nation.xml" )); //获取根元素 Element root = doc.getRootElement(); //定位到<Configuration> -> <Key> List<Element> list = root.getChildren( "Key" ); List<Element> children = new ArrayList<Element>(); List<Element> childrens = new ArrayList<Element>(); for (int i = 0; i < list.size(); i++) { Element element = (Element) list.get(i); System.out.print(element.getAttributeValue( "Name" )); //定位到<Configuration> -> <Key> -> <Value> children = element.getChildren( "Value" ); for (int j=0; j<children.size(); j++){ Element elementChildren = (Element) children.get(j); //定位到<Configuration> -> <Key> -> <Value Name="PhotoIDWidth"> if (elementChildren.getAttributeValue( "Name" ).equals( "PhotoIDWidth" )){ //获取<Configuration> -> <Key> -> <Value Name="PhotoIDWidth"> 属性值 System.out.print( "<--------->" +elementChildren.getAttributeValue( "Name" )); //获取<Configuration> -> <Key> -> <Value Name="PhotoIDWidth"> 标签里内容 System.out.print( "," +elementChildren.getText()); } } children.clear(); //定位到<Configuration> -> <Key> -> <Key> children = element.getChildren( "Key" ); for (int j=0; j<children.size(); j++){ Element elementChildren = (Element)children.get(j); //定位到<Configuration> -> <Key> -> <Key Name="Child"> if (elementChildren.getAttributeValue( "Name" ).equals( "Child" )){ //定位到<Configuration> -> <Key> -> <Key Name="Child"> -> <Value> childrens = elementChildren.getChildren( "Value" ); for (int k=0; k<childrens.size(); k++){ Element elementChildrens = (Element)childrens.get(k); //定位到<Configuration> -> <Key> -> <Key Name="Child"> -> <Value Name="HeadPercent"> if (elementChildrens.getAttributeValue( "Name" ).equals( "HeadPercent" )){ System.out.println( "<--------->" +elementChildrens.getText()); } } } } } } } 打印结果: China<--------->PhotoIDWidth,38PhotoIDWidth<--------->0.60ChildHeadPercent Australia<--------->PhotoIDWidth,35PhotoIDWidth<--------->0.711ChildHeadPercent Austria<--------->PhotoIDWidth,35PhotoIDWidth<--------->0.689ChildHeadPercent |
以上所述是小编给大家介绍的Javaweb中使用Jdom解析xml的方法,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!
原文链接:http://www.cnblogs.com/IT-1994/archive/2016/09/28/5904779.html