Web Application Architectures

• Web Application is a collection of web resources like HTML files, JavaScript files, image files, Servlets, jsp files etc… 

• In order to make resources of an application as globally accessible resources which are developed as web resources of web-application, each web-resource develops one webpage and this webpage is globally accessible page. 

• The web-application that is moved to internet network after development is called Website. 

• A web application contains two types of web-resources.  

1. 1. Server side Web-resource     

   2. Client side Web-resource 

• A web resource that comes to browser (client) from web application placed in web-server/application server for execution is called client side web resource. 

Example:  HTML, JavaScript programs.

• The web-resource program that executed in the server (web-server/application server) is called server-side web-resource program. 

Example: Servlet, JSP

A well-designed software application is partitioned into separate logical parts called layers. Each layer has a different responsibility in the overall architecture. These layers are purely abstractions, and do not correspond to physical distribution.

Typical layers in a software system are as follows:

Presentation layer/UI Layer: In this layer are parts that handle the user interface and user interaction.

Business logic layer. This layer contains components that handle the programming logic of the application.

DAO (Data Access Object) Layer/Data Layer/Persistence Layer: This layer is used by the business logic layer to persist state permanently. This layer normally consists of one or more databases where data is stored. However, other types of data store could also be used. For example, it is now very common to use XML documents as storage to keep data.

There are two architectures generally used for developing applications.

1. Model 1 Architecture 

2. Model 2 or MVC Architecture