This chapter explains:

• How to load a JavaBean into JSP pages and manipulate its properties.
• Compilation issues of using JavaBean classes in unnamed packages.
• Setting and getting JavaBeans properties.
• Using JavaBeans as Java objects in scripting elements.
• Using Java objects as JavaBeans.
• How to refresh the JavaBean objects loaded in memory.

Following is a guide to installing and configuring Apache Tomcat 6 for use as a standalone Web server (for development) that supports servlets 2.5 and JSP 2.1. (Note: Apache Tomcat is sometimes referred to as "Jakarta Tomcat" since the Apache Java effort is known as "The Jakarta Project"). This Tomcat tutorial covers version 6.0.10, but the steps are almost the same for any Tomcat 6.0.x version. For coverage of Tomcat 5.5, see the separate Tomcat 5.5 tutorial. For coverage of very old Tomcat versions (Tomcat 5.0.x and Tomcat 4.0.x), please see the Apache Tomcat 5.0 and 4.0 tutorial.

• We assume here your know what a servlets is. For more information, read first an introduction to servlets, a servlet tutorial, or Java tutorial (all links from JavaSoft).
• This article aims at presenting how to create a servlet that sends a zip file to the user. We create here a html page with a form where you can enter an url. The servlet will get the content of this url (only the html page, not the images or other frames), create a zip file with it, and send you the file.
  This example can be used as a basis to do various things.

  With this article you can have a detailed explanation about creating JSP pages and session listener class with which can count the active users of your website. The session as described in this article, is sort of temporary unique connection between the server and client, which enables the server to keep track of a specific user. The article also provides an online demo. The session can run of a servlet container or application server that supports Servlet 2.3 specification.

As you can see from previous sections, a JavaBean is just a regular Java obect. Once a JavaBean is created in a JSP, you can use JSP setProperty and getProperty action elements to set and retrieve values of its properties. To support these action elements, a JavaBean class must implement set and get methods based on some rules.