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The purpose of this module is to explain session tracking using hidden fields, and to compare a servlet with a JSP to accomplish the same objective.

Table of contents

Preface

This module is one in a collection of modules designed for teaching INEW 2338 Advanced Java (Web) at Austin Community College in Austin, TX. The purpose of this module is to explainsession tracking using hidden fields, and to compare a servlet with a JSP to accomplish the same objective.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the Figures and Listings while you are reading about them.

Figures

  • Figure 1 . The servlet user interface at startup.
  • Figure 2 . Browser display for Tom, Dick, and Harry.
  • Figure 3 . Hidden fields in the servlet output.

Listings

  • Listing 1 . Beginning of the servlet class.
  • Listing 2 . Get and save the hidden values from the browser page.
  • Listing 3 . Get and save user input data.
  • Listing 4 . Begin constructing the HTML output data.
  • Listing 5 . Begin the HTML code for an HTML form.
  • Listing 6 . An input field and a submit button.
  • Listing 7 . Beginning of the list of names.
  • Listing 8 . Display the historical data and also save it on the browser.
  • Listing 9 . Display most recent value and also store it on the browser.
  • Listing 10 . Create basic web page structure.
  • Listing 11 . A JSP scriptlet.
  • Listing 12 . The body of the for loop.
  • Listing 13 . Another scriptlet.
  • Listing 14 . Another JSP expression tag.
  • Listing 15 . Terminating scriptlet and HTML code.
  • Listing 16 . The servlet program named Java4550a.java.
  • Listing 17 . The JSP program named Java4550a.jsp.

General background information

A stateless protocol

The HTTP protocol is a relatively simple request/response protocol that does not retain historical information from one client request to the next. In otherwords, each request is a new start insofar as the HTTP server is concerned. (HTTP is sometimes referred to as a "stateless" protocol.) However, historical information can be very important. The maintenance ofhistorical information is often referred to as "session tracking."

Session tracking

Session tracking is very important for many web applications including web commerce and web games. Therefore, this and the next several modules will show you some of the ways thatyou can accomplish session tracking using servlets and JSP.

Web commerce

Perhaps the most common example of the need for session tracking is with a web commerce application involving a shopping cart. The customer (client) downloads various pages from a vendor catalog, selecting items, and placing themin a shopping cart. At some point, the customer decides either to purchase the items or abandon the shopping trip.

If the customer decides to purchase the items in the cart, the web application must have a record of all the items in the cart. Furthermore, thatrecord must be associated with that particular customer so that the sale can be consummated.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
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