dom4j之根元素、XPATH两种方式读取xml文档

    前一篇dom4j的文章  http://blog.csdn.net/undergrowth/article/details/12146003

现在使用两种方式进行读取xml文档  

   1.根元素获取下一节点的方式

   2.xpath路径的方式

不多说 东西都在代码里了 需要注释的地方以注释

package com.undergrowth.dom4j;

import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import java.util.List;

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



public class Dom4j_Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		createXml("stus.xml");
		//使用根节点的方式获取节点元素
		readXmlNode("stus.xml");
		
		System.out.println("-----------------------------XPATH获取元素----------------");
		//使用xpath的方式读取元素
		readXPathNode("stus.xml");
	}

	//以xpath的方式获取元素
	private static void readXPathNode(String path) {
		// TODO Auto-generated method stub
		Document document=parseXmlDocument(path);
		//获取student元素
		List stuList=document.selectNodes("//student");
		iteratorListElement(stuList);
		//获取特定的元素
		System.out.println("---------获取特定元素-------");
		List<Attribute> ageList=document.selectNodes("//age/@type"); 
		iteratorListAttribute(ageList);
	}

	//迭代列表属性
	private static void iteratorListAttribute(List<Attribute> ageList) {
		// TODO Auto-generated method stub
		for (Attribute object : ageList) {
			System.out.println(object.asXML());
		}
	}

	//迭代列表元素
	private static void iteratorListElement(List stuList) {
		for (Iterator iterator = stuList.iterator(); iterator.hasNext();) {
			Element stuElement = (Element) iterator.next();
			iteratorAttribute(stuElement);
			iteratorNextElement(stuElement);
		}
	}

	//使用根节点的方式获取元素
	private static void readXmlNode(String path) {
		// TODO Auto-generated method stub
		Document document=parseXmlDocument(path);
		Element rootElement=document.getRootElement();
		//遍历根元素的属性集合
		//System.out.print("根元素的属性为:	");
		iteratorAttribute(rootElement);
		//System.out.println();
		//遍历根元素的子元素
		for (Iterator iterator = rootElement.elementIterator("student"); iterator.hasNext();) {
			Element stuElement = (Element) iterator.next();
			System.out.println(stuElement.getName()+"元素");
			//遍历元素的下一级元素
			iteratorNextElement(stuElement);
		}
	}

	//迭代当前元素的下一级所有元素
	private static void iteratorNextElement(Element stuElement) {
		Iterator  iterator2=stuElement.elementIterator();
		while (iterator2.hasNext()) {
			Element nextElement = (Element) iterator2.next();
			//判断元素是否有属性
			if(nextElement.attributeCount()!=0){
				iteratorAttribute(nextElement);
			}
			System.out.println(nextElement.getName()+"元素"+",值为"+nextElement.getText());
		}
	}

	//迭代元素的属性
	private static void iteratorAttribute(Element rootElement) {
		System.out.println(rootElement.getName()+"元素");
		for (Iterator iterator = rootElement.attributeIterator(); iterator.hasNext();) {
			Attribute type = (Attribute) iterator.next();
			System.out.println(type.getName()+":"+type.getText()+"	");
			
		}
	}

	//解析返回一个文档对象
	private static Document parseXmlDocument(String path) {
		// TODO Auto-generated method stub
		SAXReader reader=new SAXReader();
		
		Document document=null;
		try {
			document=reader.read(new File(path));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		return document;
	}

	//创建xml文件
	private static void createXml(String path) {
		// TODO Auto-generated method stub
		Document document=createDocument();
		writeXml(path,document);
	}

	//将document写入到输出文件中
	private static void writeXml(String path, Document document) {
		// TODO Auto-generated method stub
		//为输出流创建格式
		OutputFormat format=OutputFormat.createPrettyPrint();
		XMLWriter writer=null;
		try {
			writer = new XMLWriter(new FileWriter(path), format);
			//将document写入到文件中
			writer.write(document);
			writer.close();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

	//创建document
	private static Document createDocument() {
		// TODO Auto-generated method stub
		Document document=DocumentHelper.createDocument();
		//在document中创建根元素students
		Element rootElement=document.addElement("students");
		rootElement.addAttribute("name", "基础与信息工程学院");
		rootElement.addComment("人数总数");
		rootElement.addAttribute("count", "2");
		
		//添加student信息
		Element stuElement=rootElement.addElement("student");
		stuElement.addElement("name").addText("刘德华");
		stuElement.addElement("age").addAttribute("type", "int").addText("28");
		//添加student信息
		Element stuElement2=rootElement.addElement("student");
		stuElement2.addElement("name").addText("黎明");
		stuElement2.addElement("age").addText("54");
		
		return document;
	}

}

结果

students元素
name:基础与信息工程学院	
count:2	
student元素
name元素,值为刘德华
age元素
type:int	
age元素,值为28
student元素
name元素,值为黎明
age元素,值为54
-----------------------------XPATH获取元素----------------
student元素
name元素,值为刘德华
age元素
type:int	
age元素,值为28
student元素
name元素,值为黎明
age元素,值为54
---------获取特定元素-------
type="int"

错误

-----------------------------XPATH获取元素----------------
Exception in thread "main" java.lang.NoClassDefFoundError: org/jaxen/JaxenException
at org.dom4j.DocumentFactory.createXPath(DocumentFactory.java:230)
at org.dom4j.tree.AbstractNode.createXPath(AbstractNode.java:207)
at org.dom4j.tree.AbstractNode.selectNodes(AbstractNode.java:164)
at com.undergrowth.dom4j.Dom4j_Test.readXPathNode(Dom4j_Test.java:40)
at com.undergrowth.dom4j.Dom4j_Test.main(Dom4j_Test.java:32)
Caused by: java.lang.ClassNotFoundException: org.jaxen.JaxenException
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 5 more

添加 jaxen-1.1-beta-6.jar 即可