DZone
Java Zone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
  • Refcardz
  • Trend Reports
  • Webinars
  • Zones
  • |
    • Agile
    • AI
    • Big Data
    • Cloud
    • Database
    • DevOps
    • Integration
    • IoT
    • Java
    • Microservices
    • Open Source
    • Performance
    • Security
    • Web Dev
DZone > Java Zone > Using Cookies to implement a RememberMe functionality

Using Cookies to implement a RememberMe functionality

Mihai Dinca - Panaitescu user avatar by
Mihai Dinca - Panaitescu
·
Jun. 26, 12 · Java Zone · Interview
Like (1)
Save
Tweet
50.70K Views

Join the DZone community and get the full member experience.

Join For Free

Some web applications may need a "Remember Me" functionality. This means that, after a user login, user will have access from same machine to all its data even after session expired. This access will be possible until user does a logout.

If you are using Spring  and its login form, then you should use "Remember Me" functionality already implemented inside the framework.

Some web frameworks also offer a type of SignIn panel which already has "remember me" built-in.

But in case you have to implement "Remember Me" functionality by your own, this can be easily achieved using Cookies. Java has a Cookie class named javax.servlet.http.Cookie.

Algorithm is straight-forward:

  1. your login panel must contain a "Remember Me" check
  2. after a succesfull login with "Remember Me" check selected, you can create two cookies: one to keep the value for rememberMe and one to keep  a token which has to identify the logged user. For sake of security, this token must never contain user name or user password. The ideea is to   generate a random id as token value. And token value aside with user id must be saved in your storage (database)
  3. whenever a login is needed, you have to look if there is any cookie saved by you, and if so and your "rememberMe" value is true, you can take the user from storage based on your token and do an automatic login.
  4. when a logout is done, you have to delete the cookie that keeps the token

 

To add a cookie, you have to specify the maximum age of the cookie in seconds :

     HttpServletResponse servletResponse = ...;
Cookie c = new Cookie(COOKIE_NAME, encodeString(uuid));
c.setMaxAge(365 * 24 * 60 * 60); // one year
servletResponse.addCookie(c);
        

To delete a cookie, you have to find cookie by name and set its maximum age to 0, before adding it to servlet response:

     HttpServletRequest servletRequest = ...;
HttpServletResponse servletResponse = ... ;
Cookie[] cookies = servletRequest.getCookies();                
for (int i = 0; i < cookies.length; i++) {
     Cookie c = cookies[i];            
    if (c.getName().equals(COOKIE_NAME)) {        
         c.setMaxAge(0);
         c.setValue(null);
         servletResponse.addCookie(c);    
          }
    }        

 

Framework application Data (computing) Session (web analytics) Machine security Java (programming language) Form (document) Spring Framework

Opinions expressed by DZone contributors are their own.

Popular on DZone

  • 6 Things Startups Can Do to Avoid Tech Debt
  • 10 Steps to Become an Outstanding Java Developer
  • Ultra-Fast Microservices: When Microstream Meets Wildfly
  • Composable Architecture

Comments

Java Partner Resources

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • MVB Program
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 600 Park Offices Drive
  • Suite 300
  • Durham, NC 27709
  • support@dzone.com
  • +1 (919) 678-0300

Let's be friends:

DZone.com is powered by 

AnswerHub logo