Introduction to Servlets

Imagine you're building a website, and you want it to be dynamic and responsive, like it can remember your preferences or fetch real-time data without reloading the entire page. That's where servlets come in handy!

Servlets are like little helpers for your web server. They're Java classes that work behind the scenes to handle requests and generate dynamic web content. They make your website interactive and efficient.

Think of servlets as the chefs in a busy kitchen. When someone orders a dish (requests a webpage), servlets swing into action, gathering ingredients (data), cooking up the dish (generating the webpage), and serving it hot to the customer (sending the webpage to the browser).

What is servlets?

At its core, a servlet is a Java class that extends the functionality of a web server. When a user interacts with a website, their browser sends a request to the server for a particular resource, like a webpage or an image. Servlets intercept these requests and provide a way for the server to dynamically generate or process the response before sending it back to the user's browser.

Think of servlets as the traffic cops of the web world. They receive requests from browsers, direct them to the appropriate resources or processes within the server, and then send back the corresponding responses.

Servlets can handle a wide range of tasks, from processing form submissions and managing user sessions to accessing databases and generating dynamic content. They're incredibly versatile and can be used to build complex web applications with ease.

Common Gateway Interface (CGI)

Imagine you're throwing a big party and you've hired a team of caterers. Each caterer has a specific job: one grills burgers, another prepares salads, and a third one serves drinks. The party guests (web users) place their orders with the caterers, who then work together to fulfill those orders and keep the party going smoothly.

In the world of web development, CGI serves a similar purpose. It's a protocol that allows web servers to communicate with external programs, known as CGI scripts, to generate dynamic web content. These scripts can be written in various programming languages like C,C++ etc.

When a user requests a resource from a website that utilizes CGI, the web server identifies the request and forwards it to the appropriate CGI script. Just like our party caterers, the CGI script then swings into action, processing the request and generating the necessary content dynamically. This could be anything from displaying the results of a search query to processing form data submitted by the user.

CGI scripts are incredibly versatile and can perform a wide range of tasks, making them essential tools for creating interactive and dynamic web applications. However, it's worth noting that CGI has some limitations, particularly in terms of performance and security, which has led to the development of alternative technologies like servlets and server-side scripting languages.

Terminology

Term	Description
HTML (Hypertext Markup Language)	A markup language used to structure content on the web by defining elements like headings, paragraphs, and links.
CSS (Cascading Style Sheets)	A style sheet language used to control the presentation of HTML documents, defining aspects like colors, fonts, and layout.
JavaScript	A programming language that adds interactivity and dynamic behavior to web pages, executed by the user's web browser.
URL (Uniform Resource Locator)	The address used to access resources on the web, typically consisting of a protocol, domain name, and path to the resource.
HTTP (Hypertext Transfer Protocol)	The protocol used for transferring data over the web, defining how messages are formatted and transmitted between clients and servers.
HTTPS (Hypertext Transfer Protocol Secure)	A secure version of HTTP that encrypts data sent between the client and server, commonly used for transmitting sensitive information.
Server	A computer or software program that provides resources or services to other computers (clients) over a network, storing and delivering web pages and files.
Client	A computer or software program that requests resources or services from a server, such as web browsers like Chrome, Firefox, and Safari.