Java Servlet Programing Laungage

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
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_3_0.xsd">
 <servlet>
  <servlet-name>writeInFileServlet</servlet-name>
  <servlet-class>r4r.servlet.writeInFileServlet</servlet-class>
 </servlet>
 <servlet-mapping>
 <servlet-name>writeInFileServlet</servlet-name>
  <url-pattern>/writeInFileServlet</url-pattern>
 </servlet-mapping>
 <session-config>
  <session-timeout>
    30
  </session-timeout>
  </session-config>
</web-app>

Index.jsp

<%-- 
Document   : index.jsp
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
 <head>
  <meta http-equiv="Content-Type"
                  content="text/html; charset=UTF-8">
  <title>r4r.co.in-servlet</title>
 </head>
 <body>
  <form>
  <h1>Access Servlet by servlet's Name!</h1>
  <a href="writeInFileServlet">writeInFileServlet</a>
  </form>
 </body>
</html>

Servlet Program

/*
 * Save as a writeInFileServlet.java
 */
package r4r.servlet;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 *
 * @author R4R
 */
public class writeInFileServlet extends HttpServlet {
private static final String FILE_PATH = 
	 "c:/Temp/r4r_BlankFile.txt";

protected void processRequest
 (HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
/* TODO output your page here */
out.println("<html>");
out.println("<head>");
out.println("<title>" + getServletInfo() + "</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet writeInFileServlet at " 
	   + request.getContextPath() + "</h1>");
out.println("<form name=\"form\" action=\
              "writeInFileServlet\" method=\"POST\" >");
out.println("Write Data into File: ");
out.println("<textarea name=\"fileData\" rows=\
                "4\" cols=\"30\" /></textarea>");
out.println("<BR><input type=\"submit\
              " value=\"Write In File\" />");
out.println("<input type=\"reset\" value=\" Reset \" />");
out.println("</form>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}

@Override
protected void doGet
(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}

@Override
protected void doPost
	(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
// Get value form textArea
String fileData = request.getParameter("fileData");
// User can't allow to leave TextArea empty
if (!fileData.equals("")) {
//  Convenience class for writing character files
FileWriter fileWriter = new FileWriter(FILE_PATH);
fileWriter.write(fileData, 0, fileData.length());
fileWriter.close();
out.println("Data successfully write into File, put on path : " 
	       + "<b>" + FILE_PATH + "</b>");
} else {
out.println("Please Don't leave any block empty !");
out.println
("<BR><a href=\"writeInFileServlet\">Return to Home Page</a>");
}
out.close();
}

@Override
public String getServletInfo() {
return "r4r.co.in- writeInFileServlet";
}
}