java读写XML文件

package editXML;

import java.io.File;

import java.io.FileOutputStream;

import java.io.PrintWriter;



import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.transform.OutputKeys;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;



import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;



public class w3c_Xml {

	

	static DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

	static DocumentBuilder builder = null;

	

 public static void readXML() {

  try {

	  builder = factory .newDocumentBuilder();   

	  Document document = builder.parse(new File("E:\\testFiles\\test.xml"));

	  Element rootElement = document.getDocumentElement();



	  NodeList list = rootElement.getElementsByTagName("Header");

	  Element element = (Element) list.item(0);

	  System.out.println(element.getChildNodes().item(0).getNodeValue());



  } catch (Exception e) {

	  System.out.println("exception:" + e.getMessage());

  }

 }

 

 public static void writeXML(Document document,String filename)

 {

	 try {

		 builder = factory .newDocumentBuilder();   

		 //Document document = builder.parse(new File("E:\\testFiles\\test.xml"));

		 document.normalize(); 

		 

		 /** 将document中的内容写入文件中 */

		 TransformerFactory tFactory = TransformerFactory.newInstance();

		 Transformer transformer = tFactory.newTransformer();

		 transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");

		 transformer.setOutputProperty(OutputKeys.INDENT, "yes");

		 //编码

		 DOMSource source = new DOMSource(document);

		 PrintWriter pw = new PrintWriter(new FileOutputStream(filename));

		 StreamResult result = new StreamResult(pw);

		 transformer.transform(source, result);

	 } catch (Exception e) {

			e.printStackTrace();

		}

	 

 }

 

 public static void updateXML()

 {

	 try {

		builder = factory .newDocumentBuilder();

		Document document = builder.parse(new File("E:\\testFiles\\test.xml"));

		Node root = document.getDocumentElement();

		/**如果root有子元素*/

		if(root.hasChildNodes())

		{

			NodeList ftpnodes = root.getChildNodes();

			/**循环取得ftpnodes所有节点*/

			for(int i=0;i<ftpnodes.getLength();i++)

			{

				Node ftpList = ftpnodes.item(i);

				System.out.println(ftpList.getTextContent());

			}

			for(int i=0;i<ftpnodes.getLength();i++)

			{

				Node ftpList = ftpnodes.item(i);

				ftpList.setTextContent(ftpList.getTextContent()+" update");

			}

		}

		writeXML(document,"E:\\testFiles\\test2.xml");

		

	 } catch (Exception e) {

		e.printStackTrace();

	 }  

 }

 

 

 public static void main(String[] args)

 {

	 //read

	 readXML();

	 //write

	 //writeXML(document,"E:\\testFiles\\test.xml");

	 //update

	 updateXML();

 }

}

test.xml

 

 

  
    

   
     
   
     <?
   
     xml version="1.0" encoding="ISO-8859-1"
   
     ?>
   
     

   
     <
   
     note
   
     >
   
     
 
   
     <
   
     to
   
     >
   
     George
   
     </
   
     to
   
     >
   
     
 
   
     <
   
     from
   
     >
   
     John
   
     </
   
     from
   
     >
   
     
 
   
     <
   
     heading
   
     >
   
     Reminder
   
     </
   
     heading
   
     >
   
     
 
   
     <
   
     body
   
     >
   
     Don't forget the meeting!
   
     </
   
     body
   
     >
   
     

   
     </
   
     note
   
     >