Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.

Chapter

his chapter gives a quick overview of servlets and JavaServer Pages

(JSP), outlining the major advantages of each. It then summarizes

T

how to obtain and configure the software you need to write servlets

and develop JSP documents.

1.1 Servlets

Servlets are Java technology's answer to Common Gateway Interface (CGI)

programming. They are programs that run on a Web server, acting as a mid 

dle layer between a request coming from a Web browser or other HTTP cli 

ent and databases or applications on the HTTP server. Their job is to:

1. Read any data sent by the user. 

This data is usually entered in a form on a Web page, but could 

also come from a Java applet or a custom HTTP client program.

2. Look up any other information about the request that is 

embedded in the HTTP request. 

This information includes details about browser capabilities, 

cookies, the host name of the requesting client, and so forth.

5