对XML文档进行分析的三个实例

第一个实例：使用DOM访问XML的程序

package org.xml.filterExam;

import java.io.*;

import javax.xml.parsers.*;

import org.w3c.dom.*;
public class DomStudentInfo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
		try
		{
			DocumentBuilder db=factory.newDocumentBuilder();
			File file=new File("NewFile.xml");
			Document doc=db.parse(file);

			NodeList nl=doc.getElementsByTagName("student");

			int len=nl.getLength();
			for(int i=0;i<len;i++)
			{
				Element element=(Element)nl.item(i);

				Node elementName=element.getElementsByTagName("name").item(0);
				Node elementAge=element.getElementsByTagName("age").item(0);

				String name=elementName.getFirstChild().getNodeValue();
				String age=elementAge.getFirstChild().getNodeValue();

				System.out.println("姓名：");
				System.out.println(name);
				System.out.println("年龄：");
				System.out.println(age);
				System.out.println("-----");
			}
		}
		catch(Exception e)
		{
			System.out.println("DomStudentInfo has a problem:"+e.toString());
		}
	}

}

第二个实例：功能是遍历文档树中的所有节点，然后依次输出节点的名字和节点的值。

package org.xml.filterExam;

import java.io.*;

import javax.xml.parsers.*;

import org.w3c.dom.*;

public class DOMPrinter {

	public static void PrintNodeInfo(Node node)
	{
		System.out.println(node.getNodeName()+" : "+node.getNodeValue());
	}

	public static void printNode(Node node)
	{
		short nodeType=node.getNodeType();
		switch(nodeType)
		{
		case Node.PROCESSING_INSTRUCTION_NODE:
			System.out.println("------PI start------");
			PrintNodeInfo(node);
			System.out.println("------PI End--------");
			break;
		case Node.TEXT_NODE:
			System.out.println("------Text Start------");
			PrintNodeInfo(node);
			System.out.println("------Text End------");
			break;
		case Node.ELEMENT_NODE:
			System.out.println("------Element start------");
			PrintNodeInfo(node);
			System.out.println("------Element End------");

			NamedNodeMap attrs=node.getAttributes();
			int attrNum=attrs.getLength();
			for(int i=0;i<attrNum;i++)
			{
				Node attr=attrs.item(i);
				System.out.println("------Attribute start------");
				PrintNodeInfo(attr);
				System.out.println("------Attribute End------");
			}
			break;
		default:
			break;
		}
		Node child=node.getFirstChild();
		while(child!=null)
		{
			printNode(child);
			child=child.getNextSibling();
		}
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
		try
		{
			DocumentBuilder db=dbf.newDocumentBuilder();
			Document doc=db.parse(new File("NewFile.xml"));
			printNode(doc);
		}
		catch(Exception e)
		{
			System.out.println("DOMPrinter has a problem :"+e.toString());
		}
	}

}

第三个实例：添加一个结点，将修改后的信息保存到另一个XML文件中

package org.xml.filterExam;

import java.io.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.*;

public class DOMConvert {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
		try
		{
			DocumentBuilder db=dbf.newDocumentBuilder();
			Document doc=db.parse(new File("NewFile.xml"));

			Element eleStu=doc.createElement("student");
			Element eleName=doc.createElement("name");
			Element eleAge=doc.createElement("age");

			Attr attr=doc.createAttribute("sn");
			attr.setValue("03");
			Text textName=doc.createTextNode("haha");
			Text textAge=doc.createTextNode("30");

			eleName.appendChild(textName);
			eleAge.appendChild(textAge);

			eleStu.appendChild(eleName);
			eleStu.appendChild(eleAge);
			eleStu.setAttributeNode(attr);

			Element eleRoot=doc.getDocumentElement();
			eleRoot.appendChild(eleStu);

			DOMSource source=new DOMSource(doc);

			StreamResult result=new StreamResult(new File("NewFile2.xml"));

			TransformerFactory tff=TransformerFactory.newInstance();

			Transformer tf=tff.newTransformer();

			tf.transform(source, result);

		}
		catch(Exception e)
		{
			System.out.println("DOMConvert has a problem "+e.toString());
		}

	}
}