Servlets are generic extensions to Java-enabled
servers. Their most common use is to extend Web servers, providing a very
secure, portable, and easy-to-use replacement for CGI. A servlet is a
dynamically loaded module that services requests from a Web server. It
runs entirely inside the Java Virtual Machine. Because the servlet is
running on the server side, it does not depend on browser compatibility.
Practical Applications for Java Servlets
Servlets can be used for
any number of Web-related applications. The following are three examples
:
Developing e-commerce "store fronts" will become one of
the most common uses for Java servlets. A servlet can build an online
catalog based on the contents of a database. It can then present this
catalog to the customer using dynamic HTML. The customer will choose
the items to be ordered, enter the shipping and billing information,
and then submit the data to the servlet. When the servlet receives the
posted data, it will process the orders and place them in the database
for fulfillment. Every one of these processes can be easily implemented
using Java servlets.
Servlets can be used to deploy Websites that open up large legacy
systems on the Internet. Many companies have massive amounts of data
stored on large mainframe systems. These businesses do not want to re-architect
their systems, so they choose to provide inexpensive Web interfaces
into them. Because you have the entire JDK at your disposal and security
provided by the Web server, you can use servlets to interface into these
systems using anything from TCP/IP to CORBA.
These are just two examples of the power and practicality of using Java
servlets. Servlets are very viable options for most Web applications.
