Desenvolvimento jsp

Introducing JSP and Tomcat
Interactivity is what makes the Web really useful. By interacting with a remote server, you can find the information you need, keep in touch with your friends, or purchase something online. And every time you type something into a web form, an application “out there” interprets your request and prepares a web page to respond.
To understand JSP, you first need to have a clear idea of what happens when you ask your browser to view a web page, either by typing a URL into the address field of your browser or by clicking on a hyperlink. Figure 1-1 shows you how it works.
Figure 1-1. Viewing a plain HTML page
The following steps show what happens when you request your browser to view a static web page:
1. When you type an address such as http://www.website.com/path/whatever.html into the address field, your browser first resolves www.website.com (i.e., the name of the web server) into the corresponding Internet Protocol (IP) address, usually by asking the Domain
Name Server provided by your Internet Service Provider (ISP). Then your browser sends an HTTP request to the newly found IP address to receive the content of the file identified by /path/whatever.html.
2. In reply, the web server sends an HTTP response containing a plain-text HTML page. Images and other non-textual components, such as sound and video clips, only appear in the page as references.
3. Your browser receives the response, interprets the HTML code contained in the page, requests the non-textual components from the server, and displays the lot.
JavaServer Pages (JSP) is a technology that helps you create such dynamically generated pages by converting script files into executable Java modules;
JavaServer Faces (JSF) is a package that facilitates interactivity with the page viewers; and Tomcat is an application that can execute your code and act as a web server for your dynamic pages.
Everything you need to develop JSP/JSF web applications is available for free