Stored Data in XML File using Servlet

In this section, you will learn how to stored data in xml file using Servlet We have created file login.jsp,XmlServlet.java. User details in the "login.jsp" are to be stored in xml file. It creates XML file with its version and encoding and display a message 'Xml File Created Successfully'.

JAXP (Java API for XML Processing) is a Java interface that provides a standard approach to Parsing XML documents. With JAXP, we will use the Document BuilderFactory to create DocumentBuilder class. The class DocumentBuilderFactory is responsible for creating new DOM .

DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = builderFactory .newDocumentBuilder();DocumentBuilderFactory is used to find the class to load.

The instance of the class DocumentBuilder is used to create a blank document.

Document doc = docBuilder.newDocument();

Step 1: Create a web page "login.jsp"

<html>

    <head>

    </head>

    <body>

    <br>

    <br>

    <form name="loginform" method="post" action="xmlServlet">

    <table align="center" style="border:1px solid #000000;" bgcolor="#efefef">

   <tr>

		<td colspan=2 align="center" style="font-weight:bold;">UserLogin</td>

    

	</tr>

	<tr>

		<td>User Name</td>

		<td><input type="text" name="username" value=""></td>

	</tr>

	<tr>

		<td>Password</td>

		<td><input type="password" name="password" value=""></td>

	</tr>

    

	<tr>

		<td></td>

		<td><input type="submit" name="Submit" value="Save"></td>

	</tr>

    </table>

    </form>

    </body>

    </html>

Step 2:Create a Servlet "XmlServlet.java".


import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;



import java.io.*;

import org.w3c.dom.*;

import javax.xml.parsers.*;

import javax.xml.transform.*;

import javax.xml.transform.dom.*;

import javax.xml.transform.stream.*;  



public class XmlServlet extends HttpServlet{ 

  public void doPost(HttpServletRequest request, HttpServletResponse response)

                                   throws ServletException,IOException{

    response.setContentType("text/html");

    PrintWriter pw = response.getWriter();

  String username="";

  String password="";



  if(request.getParameter("username")!=null && request.getParameter("password")!=null)

    {

           username = request.getParameter("username").toString();

       password = request.getParameter("password").toString();

    }

  try

  {

    DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();

        DocumentBuilder docBuilder = builderFactory.newDocumentBuilder();

        //creating a new instance of a DOM to build a DOM tree.

        Document doc = docBuilder.newDocument();

        new XmlServlet().createXmlTree(doc,username,password);

    

    pw.println("<b>Xml File Created Successfully</b>");

  }

  catch(Exception e)

  {

    System.out.println(e);

  }

     

  }



  public void createXmlTree(Document doc,String userid,String password) throws Exception {

        //This method creates an element node

        Element root = doc.createElement("User");

        //adding a node after the last child node of the specified node.

        doc.appendChild(root);



       



        Element child1 = doc.createElement("UserId");

        root.appendChild(child1);



        Text text = doc.createTextNode(userid);

        child1.appendChild(text);



       



        Element element = doc.createElement("Password");

        root.appendChild(element);



        Text text1 = doc.createTextNode(password);

        element.appendChild(text1);



       

       

     //TransformerFactory instance is used to create Transformer objects. 

        TransformerFactory factory = TransformerFactory.newInstance();

        Transformer transformer = factory.newTransformer();

       

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



        // create string from xml tree

        StringWriter sw = new StringWriter();

        StreamResult result = new StreamResult(sw);

        DOMSource source = new DOMSource(doc);

        transformer.transform(source, result);

        String xmlString = sw.toString();



        File file = new File("c:/loginXml.xml");

        BufferedWriter bw = new BufferedWriter

                      (new OutputStreamWriter(new FileOutputStream(file)));

        bw.write(xmlString);

        bw.flush();

        bw.close();

      

    }

}

Step 3:Create a web.xml for mapping Servlet "XmlServlet.java".

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

<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">

<display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
<servlet>
<servlet-name>xmlservlet</servlet-name>
<servlet-class>XmlServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>xmlservlet</servlet-name>
<url-pattern>/xmlServlet</url-pattern>
</servlet-mapping>

</web-app>