How to expire and destroy Cookies in JSP and Servlets ?

A simple application to demonstrate how to expire and destroy Cookies in JSP and Servlets

Step 1 : Create index.jsp

Here index.jsp just transfer control / request to cookies.jsp

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<%@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="Refresh" content="0; URL=cookies.jsp">
    </head>
    <body>
    </body>
</html>

Step 2 : Create mystyle.css

Here mystyle.css is just for providing style to JSP page. Things will also work without using it.

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<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
 pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1">
<title>Adding Cookies</title>
<link href="mystyle.css" rel="stylesheet" type="text/css">
</head>
<body>
 <%@ page import="javax.servlet.http.Cookie;"%>
 <form method="post" action="cookies.jsp">
  <p>&nbsp;</p>
  <p align="center" class="black">Enter cookie name and cookie
   value.</p>
  <table align="center" bgcolor="#728DCF">
   <tr>
    <td>Cookie Name</td>
    <td><input name=name size=20 class="smalltext"></td>
   </tr>
   <tr>
    <td>Cookie Value</td>
    <td><input name=value size=20 class="smalltext"></td>
   </tr>

   <tr>
    <td colspan="2" align="center"><input type="submit"
     value="Add Cookie" /></td>
   </tr>
  </table>
 </form>
 </td>
 </tr>
 <tr>
  <td>&nbsp;</td>
 </tr>
 </table>

 <%
  // Checks for the value of name that it is null or not
  String name = request.getParameter("name");
  if (name != null && name.length() > 0) {
   String value = request.getParameter("value");
   Cookie retrieveCookies = new Cookie(name, value);
   // Setting the max age of Cookie to 5 minute 
   retrieveCookies.setMaxAge(5 * 60);
   // add cookies to response object of jsp 
   response.addCookie(retrieveCookies);
   // redirects control to same page for new request
   response.sendRedirect("cookies.jsp");
  }
 %>

 <p>&nbsp;</p>
 <p align="center" class="black">Cookies used so far ...</p>
 <table align="center" cellpadding="1" cellspacing="1" border="1"
  bgcolor="#728DCF">
  <tr bgcolor="#000000">
   <td>Cookie Name</td>
   <td>Cookie Value</td>
  </tr>

  <%
   // getCookies() method returns array of Cookie 
   // we iterate over it and extract the name and value
   // into seperate variables cookieName and cookieValue
   Cookie[] cookies = request.getCookies();
   for (int i = 0; i < cookies.length; i++) {
    Cookie cookie = cookies[i];
    String cookieName = cookie.getName();
    String cookieValue = cookie.getValue();
    // display each value on jsp by iterating one by one

    // Above we have set the max age to be 5 minutes, in order
    // to destroy a cookie completely now say before expiration
    // we perform a check over the cookie name we want to destroy
    // let for example we want to destroy cookie with name "BOOKS"
    // after 1 minute ... below is the procedure to destroy it  ... 
    if (cookieName.equals("BOOKS")) {
     // first creating a new cookie with name same as our old cookie
     // setting the value of cookie to empty or null
     Cookie booksCookie = new Cookie("BOOKS", "");
     // second setting the max age to be 1 minutes here books 
     // should have stayed 5 minutes but we are destorying it
     // early ... both steps are necessary because if we not 
     // follow the first step cookie value will remain there 
     // till brower window is closed
     booksCookie.setMaxAge(1 * 60);
     response.addCookie(booksCookie);
    }
  %>
  <tr>
   <td><%=cookieName%></td>
   <td><%=cookieValue%></td>
  </tr>

  <%
   }
  %>
 </table>
</body>
</html>