Session Tracking

• HTTP connections are not persistent, meaning that the user is anonymous from request to request.
• But most applications require some type of persistence, so we have to associate some type of unique ID to the user that can be used from request to request.
• We can do this a few ways:
• Cookies are text data written to the user's hard drive.  These cookies can contain a unique identifier, and an expriation time.  But, cookies can be disabled.
• URL Rewriting means we put the key in the query string (parameter list) of the URL.  Thus, we write URLs, such as links and actions for <FORM> tags, dynamically.  But, unlike cookies, this information is not kept when the browser is closed.
• Hidden Fields are similiar to URL Rewriting.  We just put the unique ID in a hidden field that is passed through the URL when a form is submitted.
• Fortunately, Java handles a lot of this for us, if we choose.
• The HttpSession object automatically handles sessions for us. If the browser accepts cookies, it will use a cookie.  If not, it will use some type of URL Rewriting.
• With this, we can acutally pass Java objects across pages.

Created by:  Brandan Jones December 17, 2001