Where To Put Data Access Layer In Mvc

Three Tier (Three Layer) Architecture in Spring MVC Web Application

In this commodity, we will discuss how to create three-layer architecture in Spring MVC web applications.

In this article, we will discuss:
1. Three Tier (3 Layer) Architecture
ii. Three Tier (Iii Layer) Compages VS MVC Pattern
three. How to use Iii-layer architecture in Spring MVC web applications.

Learn Jump MVC at https://www.javaguides.net/p/leap-mvc-tutorial.html

Video

This article explained in beneath YouTube video:

1. Three Tier (3 Layer) Compages

3-tier (or three-layer) architecture is a widely accepted solution to organize the codebase. According to this compages, the codebase is divided into three split layers with distinctive responsibilities:

Presentation layer: This is the user interface of the application that presents the application's features and data to the user.

Business logic (or Application) layer: This layer contains the concern logic that drives the application's core functionalities. Like making decisions, calculations, evaluations, and processing the information passing betwixt the other 2 layers.

Data access layer (or Data) layer: This layer is responsible for interacting with databases to salve and restore application information.

2. Three Tier (Three Layer) Architecture VS MVC Pattern

Let'due south run across how these ii architectural patterns (both containing three connected components) relate to each other.

The MVC pattern is only concerned with organizing the logic in the user interface (presentation layer).

As the name implies, the MVC pattern has iii layers: The Model defines the business organization layer of the application, the Controller manages the flow of the awarding, and the View defines the presentation layer of the application.

The Model Layer - This is the data layer which contains the business organization logic of the system, and also represents the state of the application. It's independent of the presentation layer, the controller fetches the data from the Model layer and sends information technology to the View layer.
The Controller Layer - The controllerlayer acts as an interface betweenViewandModel. Information technology receives requests from theViewlayer and processes them, including the necessary validations.
The View Layer - This layer represents the output of the application, usually some form of UI. The presentation layer is used to display theModeldata fetched by theController.

3-tier architecture has a broader business concern. Information technology's almost organizing the code in the whole application.

The controller component of MVC is the connectedness signal between the 2 layers:

3. How to employ Three-layer compages in Spring MVC web applications.

In a Leap MVC web application, the three layers of the architecture will manifest every bit follows:

Controller classes as the presentation layer. Proceed this layer as thin equally possible and limited to the mechanics of the MVC operations, e.g., receiving and validating the inputs, manipulating the model object, returning the appropriate ModelAndView object, and so on. All the business-related operations should be done in the service classes. Controller classes are ordinarily put in a controller packet.

Service classes as the business logic layer. Calculations, data transformations, data processes, and cross-record validations (business organization rules) are usually done at this layer. They go called by the controller classes and might phone call repositories or other services. Service classes are usually put in a service package.

Repository classes every bit data access layer. This layer's responsibility is limited to Create, Call up, Update, and Delete (CRUD) operations on a data source, which is commonly a relational or non-relational database. Repository classes are usually put in a repository package.

Consider below Spring MVC web application using Spring kick and thymeleaf. Nosotros have created a 3-layer architecture and each layer is mapped to the corresponding package.

For example:

Presentation Layer - controller package
Business Logic Layer - service parcel
Data Access Layer - repository package

Conclusion

In this commodity, we have discussed:
1. Iii Tier (Three Layer) Architecture
two. Three Tier (Three Layer) Architecture VS MVC Pattern
3. How to use Three-layer architecture in Spring MVC web applications.