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Java Servlet Sessions

  • Jul 6, 2001
In this chapter you will learn several methods that you can integrate into your servlets to handle persistent sessions. You’ll discuss the hidden form fields, persistent cookies, URL rewriting, and the Servlet API's built-in session handling support.
This chapter is excerpted from Developing Java Servlets, 2nd Edition.

In This Chapter

  • What Is Session Tracking?

  • Using Hidden Form Fields

  • Working with Cookies

  • URL Rewriting

  • Session Tracking with the Servlet API

What Is Session Tracking?

Session tracking is the capability of a server to maintain the current state of a single client's sequential requests. The HTTP protocol used by Web servers is stateless. This means that every transaction is autonomous. This type of stateless transaction is not a problem unless you need to know the sequence of actions a client has performed while at your site.

For example, an online video store must be able to determine each visitor's sequence of actions. Suppose a customer goes to your site to order a movie. The first thing he does is look at the available titles. When he has found the title he is interested in, he makes his selection. The problem now is determining who made the selection. Because each one of the client's requests is independent of the previous requests, you have no idea who actually made the final selection.

NOTE

You could use HTTP authentication as a method of session tracking, but each of your customers would need an account on your site. This is fine for some businesses, but would be a hassle for a high-volume site. You probably could not get every user who simply wants to browse through the available videos to open an account.

In this chapter, you will look at several different ways to determine the actions that a particular client has taken. You will examine hidden form fields, cookies, URL rewriting, and the built-in session tracking functionality found in the servlet API.

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