Spring Boot follows a layered architecture, commonly known as the three-tier architecture, to structure the components of a web application. This architecture divides the application into three main layers, each with its specific responsibilities:
Presentation Layer (or Web Layer):
This layer is responsible for handling user interactions and displaying data to the user. It typically includes components like controllers, which receive HTTP requests, process them, and return HTTP responses.
In Spring Boot, controllers are the primary components in the presentation layer. They handle incoming HTTP requests, interact with the service layer, and return appropriate responses.
Presentation layer objects may include DTOs (Data Transfer Objects) or ViewModel objects that help in transferring data between the presentation layer and the service layer.
Service Layer (or Business Logic Layer):
The service layer contains the business logic of the application. It handles the core processing of data and implements the application's functionality.
In Spring Boot, service classes are typically used in this layer. They encapsulate business rules, coordinate data access, and provide a high-level interface to the presentation layer.
Service layer objects often interact with data access objects (DAOs) or repositories to retrieve or store data in the database.
Data Access Layer (or Persistence Layer):
This layer is responsible for interacting with the database or any other data source. It performs CRUD (Create, Read, Update, Delete) operations and manages data persistence.
In Spring Boot, this layer is often associated with repositories or DAOs (Data Access Objects). These components provide an abstraction over data storage and retrieval.
Entities or domain objects, which represent the data structures in the application, are also part of the data access layer.
While these three layers are the core components in a Spring Boot application, it's worth noting that Spring Boot encourages a well-organized and modular codebase. In addition to these layers, you may also have other components such as:
Security Layer:
This layer handles authentication and authorization concerns. It ensures that only authorized users can access certain parts of the application.
Spring Security is a popular framework for implementing security in Spring Boot applications.
Configuration Layer:
- Spring Boot emphasizes the use of configuration files (e.g.,
application.propertiesorapplication.yml) to configure the application. Configuration classes and profiles can also be part of this layer.
- Spring Boot emphasizes the use of configuration files (e.g.,
Utility and Helper Classes:
- These are auxiliary classes that provide common functionality or utilities used across different layers of the application.
Spring Boot's flexible and modular design allows you to organize your code in a way that makes sense for your specific application's requirements while adhering to the principles of separation of concerns and modularity. The specific components and layers may vary depending on the application's complexity and design.