DOM4J学习

两个jar包：1.dom4j和jaxen

1.查询

XML文件:

<?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>

代码部分：

package com.xml.dom4j;

import java.util.List;


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

public class Dom4j {

    /**
     * @param args
     * @throws DocumentException 
     */
    public static void main(String[] args) throws DocumentException {
        SAXReader reader = new SAXReader();
        Document document = reader.read("C:\\Users\\hp\\workspace\\MyTexst\\book.xml");

        System.out.println("Root element:"+document.getRootElement().getName());

        Element classElement = document.getRootElement();

        @SuppressWarnings("unchecked")
        List<org.dom4j.Node> nodes = document.selectNodes("/class/student[@rollno='493']");
        System.out.println("-------------------------------------");

        for(org.dom4j.Node node :nodes){
            System.out.println("Element name:"+node.getName());

            System.out.println("rollno:"+node.valueOf("@rollno"));

            System.out.println("FirstName:"+node.selectSingleNode("firstname").getText());

            System.out.println("LastName:"+node.selectSingleNode("lastname").getText());

            System.out.println("NickName:"+node.selectSingleNode("nickname").getText());

            System.out.println("Marks:"+node.selectSingleNode("marks").getText());
        }

    }


}

运行结果：

Root element:class
-------------------------------------
Element name:student
rollno:493
FirstName:Vaneet
LastName:Gupta
NickName:vinni
Marks:95

2.创建

要创建的XML文件

<?xml version="1.0" encoding="UTF-8"?>

<cars>
  <supercars company="Ferrai">
    <carname type="Ferrai          101">Ferrai101</carname>
    <carname type="sports">Ferrai 202</carname>
  </supercars>
</cars>

代码：

package com.xml.dom4j;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class DOM4JCreateXMLDemo {

    /**
     * @param args
     */
    public static void main(String[] args) {
        try {
            Document document = DocumentHelper.createDocument();
            Element root = document.addElement("cars");
            Element supercarElement = root.addElement("supercars")
                    .addAttribute("company", "Ferrai");

            supercarElement.addElement("carname")
                .addAttribute("type", "Ferrai          101")
                .addText("Ferrai101");

            supercarElement.addElement("carname")
                .addAttribute("type", "sports")
                .addText("Ferrai 202");

            //这里是打印在控制台了的说
            OutputFormat format = OutputFormat.createPrettyPrint();
            XMLWriter writer;
            writer = new XMLWriter(System.out, format);
            writer.write(document);


        } catch (Exception e) {
            // TODO: handle exception
        }
    }

}

打印在控制台的结果：

<?xml version="1.0" encoding="UTF-8"?>

<cars>
  <supercars company="Ferrai">
    <carname type="Ferrai          101">Ferrai101</carname>
    <carname type="sports">Ferrai 202</carname>
  </supercars>
</cars>

3.修改XML

修改的XML文件：

<?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>

代码：

package com.xml.dom4j;

import java.io.UnsupportedEncodingException;
import java.util.Iterator;
import java.util.List;

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

public class ＤＯＭ４JModifyXMLDemo {

    /**
     * @param args
     * @throws DocumentException 
     * @throws UnsupportedEncodingException 
     */
    public static void main(String[] args) throws DocumentException, Exception {
        SAXReader reader = new SAXReader();
        Document document = reader.read("C:\\Users\\hp\\workspace\\MyTexst\\book.xml");

        Element classElement = document.getRootElement();

        List<Node> nodes = document.selectNodes("/class/student[@rollno='493']");
        for(Node node:nodes){
            Element element = (Element) node;
            Iterator iterator = element.elementIterator("marks");
            while(iterator.hasNext()){
                Element marksElement = (Element) iterator.next();
                marksElement.setText("8000");
            }
        }

        OutputFormat format = OutputFormat.createPrettyPrint();
        XMLWriter writer;
        writer = new XMLWriter(System.out,format);
        writer.write(document);
    }

}

控制台打印结果：

<?xml version="1.0" encoding="UTF-8"?>

<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>8000</marks> 
  </student>  
  <student rollno="593"> 
    <firstname>jasvir</firstname>  
    <lastname>singn</lastname>  
    <nickname>jazz</nickname>  
    <marks>90</marks> 
  </student> 
</class>