1 / 7

Sessions and the Web

Sessions and the Web. CSE 3330 Southern Methodist University. HTTP. Client. Web server. Internet. Http is a stateless protocol . Server doesn’t know the relationship (if one even exists) between various requests made from various clients.

takara
Télécharger la présentation

Sessions and the Web

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Sessions and the Web CSE 3330 Southern Methodist University

  2. HTTP Client Web server Internet • Http is a stateless protocol. • Server doesn’t know the relationship (if one even exists) between various requests made from various clients. • 15 requests to the server: could be from 1 client or from 15 different clients

  3. How can a website remember? • How can the web server remember from request to request who you are and info about your visit? • IOW: How can we track a particular user visit? • IOW: How can we maintain state between different requests from the same user? • Options: • Cookies • URL Rewriting • Session Tracking

  4. HttpSession • In a servlet, you can get access to the current user’s session from the request object HttpSessions = req.getSession(true); • You can set key-value pairs. • keys are strings • values are Java Objects s.setAttribute(“name”, “Mark Fontenot”); true here means that If a session doesn’t already exist, create one

  5. Accessing The Session Attributes • If you know the name of the attribute: String temp = (String)s.getAttribute(“Name”); • To iterate over all of the attributes: • Remember that attributes are stores as Objects. • Must cast to String type before storing in String var. • Note that this obviously won’t work if you store some other type in the session for (Enumeration<String> e = ses.getAttributeNames(); e.hasMoreElements(); ) { String key = e.nextElement(); Object val = ses.getAttribute(key.toString()); out.println("<br/>key = " + key + "; val = " + val.toString()); }

  6. 5 Seconds to HTML Forms <head><title>Simple Form</title></head> <body> <form name="input" action="setVals" method="get"> Key: <input type="text" name="k" /><br /> Value: <input type="text" name="v" /> <br /> <input type="submit" value="Submit" /> </form> </body> </html> When Submit Button is Clicked, will generate URL: http://localhost:8080/simpleservlet/setVals?k=name&v=mark

  7. Directory Structure Update

More Related