HTTP-Servlets

HTTP Basics

GET and POST
Headers and Parameters
RESTful Operations

GET and POST

Core HTTP methods for data retrieval and submission

Headers and Parameters

Define content type, language, and other request/response details

RESTful Operations

Additional HTTP methods like PUT and DELETE for resource management

Servlet Lifecycle

Methods like init(), doGet(), doPost(), and destroy().

Handling Requests

HttpServletRequest and HttpServletResponse for processing client data

Annotations

Use @WebServlet for configuration without modifying web.xml

Form Handling

Retrieve form data from client submissions

Output Formats

Generate HTML or JSON responses for diverse front

HTTP

HyperTextTransferProtocol

HTTP is used for

Web browsers and servers communication

GET

sends query parameters in the URL

POST

sends query parameters in the "payload"

Both GET and POST send

headers. Browsers do not display headers.

REST APIs use

PUT and DELETE

PUT is used to

update the records on the server

DELETE is used to

remove records from the server

ALL operations use a

"Request / Response"

The normal form of HTTP Request contains

3 fields, followed by headers:
HTTPmethod, identifier, HTTPversion

HTTP_method is

GET, POST, PUT, etc., and describes what needs to be done

Identifier is

the URL of the resource

HTTP_version is

the HTTP Protocol version, such as HTTP/2.0.

HTTP Request "headers"

header name : header value

The normal form of HTTP Response contains

3 fields, followed by headers, followed by the resource requested:
HTTPversion, Numericcode, String_code

String_code is

the text version of the numeric_code, such as OK

Dynamic Web Content allows

different data to be shown on the same web page

Most dynamic content is based on

a server program running and generating the front

backend web languages

Java :Servlets, JSP (obsolete), JavaBeans, Spring Boot
.NET : C++, C#, VB
PHP
Ruby
Python
Server_side JavaScript : Node.js
CGI

There are three frontend web languages

HTML, CSS, JavaScript

computer>apache>MySQL

Client>Web/Application Server (Server)>Database

Servlets are

Java classes that inherit from the HttpServlet class, and can serve dynamic web content

Servlets get compiled and executed on

the server and generate client

Client_side code is

HTML, CSS, and JavaScript

data" is

XML or JSON (in Ajax methodology)

Servlets can be used to

process the data submitted from an HTML form through the HttpServletRequest variable in the doGet, doPost, or service method

a popular Java Servlet framework

Spring Boot

Spring Boot tries to

remove all configuration and allow a programmer to focus solely on writing Java code