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>
* */
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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
* */
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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
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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