Session management is the process of keeping track of the activities of a user across
Web pages. Consider an example of an online shopping mall. The user can choose a
product and add it to the shopping cart. When the user moves to a different page, the
details in the shopping cart are still retained, so that the user can check the items in
- Messenger service in which the user name and the password are saved and displayed automatically as soon as you visit a web site.
- Some of the web sites track your email id and automatically start sending free subscription of their newsletters to the mail address.
activities across Web pages. However, there are certain techniques that helps store
the user information across Web pages using HTTP protocol. The techniques that you
can use to maintain the session information are:
1)Hidden form field
2)URL rewriting
3)Cookies
4)Servlet session API
Using Cookies
Cookies are small text files that are stored by an application server in the client
browser to keep track of all the users. A cookie has values in the form of name/value pairs.
Note:Cookies will not work if they are disabled in the browser.
Jsp Page:index.jsp
<%--Document : indexCreated on : Feb 28, 2012, 3:32:07 PMAuthor : dell_pc--%><%@page contentType="text/html" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>JSP Page</title></head><body><h1>Access Servlet by servlet's Name!</h1><a href="CookieServlet">CookieServlet</a><br><a href="SessionTrackerServlet">SessionTrackerServlet</a><br></body></html>
Servlet:CookieServlet
/** To change this template, choose Tools | Templates* and open the template in the editor.*/package servlet;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/**** @author dell_pc*/public class CookieServlet extends HttpServlet {private Cookie cookie;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 CookieServlet at " + request.getContextPath() + "</h1>");out.println("<form name=\"form\" action=\"CookieServlet\" method=\"POST\">");out.println("<BR>Username:");out.println("<input type=\"text\" name=\"user\" value=\"\" size=\"20\" />");out.println("<BR>Password :");out.println("<input type=\"password\" name=\"pass\" value=\"\" size=\"20\" />");out.println("<BR> <input type=\"submit\" value=\"Submit Form\" name=\"submit\" />");out.println("<input type=\"reset\" value=\"Reset \" />");out.println("</form>");out.println("</body>");out.println("</html>");} finally {out.close();}}@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {processRequest(request, response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// processRequest(request, response);response.setContentType("text/html;charset=UTF-8");PrintWriter out = response.getWriter();// get value form TextFieldString username = request.getParameter("user");String password = request.getParameter("pass");// User don't allow to leave any textfield emptyif ((!username.equals("") && (!password.equals("")))) {String cookieValue = username + " " + password;cookie = new Cookie("cookiee", cookieValue); // initialize cookiecookie.setMaxAge(100); // set cookie max agecookie.setVersion(1); // set cookie versionresponse.addCookie(cookie);out.println("<html>");out.println("<head>");out.println("<title>" + getServletInfo() + "</title>");out.println("</head>");out.println("<body>");// retrive cookiee value and display cookiee informationout.println("<b>Data successfully add into cookiee</b>");out.println("<br>Cookiee Name: " + cookie.getName());out.println("<br>Cookiee Value : " + cookie.getValue());out.println("<br>Cookiee Version : " + cookie.getVersion());out.println("</body>");out.println("</html>");} else {out.println("Please don't leave any textfield empty!");out.println("<BR><a href=\"CookieServlet\">Return to home Page</a>");}out.close(); //close text-output stream}@Overridepublic String getServletInfo() {return "CookieServlet";}}
Output:
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