|
|
| Techniques
used for Generating Dynamic Content |
| |
|
Common
Gateway Interface (CGI) |
| For any
web application high performance and timely delivery are key
ingredients to competitive success. Earlier
CGI was developed to provide the server-side capability to web
application. Although CGI played a major role in the explosion
of Internet, it's performance, scalability and usability issues
make it less than the optimal solution. CGI runs in a separate
process separated from the web server and it requires more
hardware and software resources. CGI programs are slow because
for each a new call is to the CGI program, which subsequently
runs in a separate process. If your program needs to interact
with Web Server, using CGI program you can't accomplish it as
CGI's separate process can't interact with Web Server.
|
|
Scripting
Languages
|
To
solve all these problems several companies have developed
server-side scripting languages. These scripts are popular and
allows developers to develop web applications that generates
dynamic pages. Microsoft has developed ASP (Active Server
Pages) for IIS Server and Cold Fusion is product of Allaire. Web
Server interprets these scripts when the pages are served. These
scripting languages provide good performance but imposes the
portability issues as they are limited to particular group of
products or operating system.
|
|
Server
plug-in technologies |
Server side plug-in technology provide very good performance.
NSAPI is the plug-in from Netscape and ISAPI is from Microsoft.
Programming using these plug-in are difficult and also learning
curve is also very high.
|
|
Java
Servlets |
| Java
Servlets eliminated all these problems. The first truly platform
independent web development technique, Java Servlets breaks down
all traditional barriers giving you flexibility to run your Web
Application on any Web Server.
Built from the
ground up using Sun's write once run anywhere technology, Java
Servlets provide excellent framework to develop server-side
application without sacrificing functionality or performance.
With Java
Servlets you can finally develop your web application that can
run on any platform. Java Servlets have number of advantages
over CGI and other API's. They are:
- Platform Independence:
This is very important feature of Servlets, which makes them
portable across platforms and across different Web Servers,
because the Servlet API defines a standard interface between
a Servlet and a Web Server.
- Persistent:
Java Servlets are loaded once by a Web Server when it
receives a request from the client and serving the subsequent
request is just a matter of creating new thread. Servlets
can maintain system resources (e.g.. database connectivity
etc.) between requests, thus making it easy to share
resources like database connectivity.
- Familiarity:
Servlets are written in Java Language, so anyone having
some programming knowledge in Java can learn Servlets
easily. This saves saves the valuable time of learning a new
programming language.
In the next
section we learn about JDBC and see how to use JDBC to connect
our search engine to database.
|
|
|
 |
|
|
|
