Spring Boot Architecture

1. Introduction

Spring Boot is built on top of Spring Framework.

It helps to:

• Reduce boilerplate code

• Provide auto-configuration

• Run applications with embedded servers

Spring Boot is used to build:

• Standalone applications

• Scalable systems

• Production-ready applications

2. Spring Boot Architecture Layers

Spring Boot architecture is divided into four layers:

1. Presentation Layer

2. Business Layer

3. Persistence Layer

4. Database Layer

3. Presentation Layer

This is the entry point of the application.

Responsibilities

• Handles HTTP requests (GET, POST, PUT, DELETE)

• Exposes REST APIs

• Validates request data

• Converts Java objects to JSON

• Sends response to client

• Calls Service layer

Common Annotations

• @RestController / @Controller

• @RequestMapping

• @GetMapping, @PostMapping

• @RequestBody

• @PathVariable

4. Business Layer (Service Layer)

This layer contains business logic.

Responsibilities

• Implements business rules

• Processes data

• Handles authentication and authorization

• Manages transactions

• Calls repository layer

Common Annotations

• @Service

• @Transactional

5. Persistence Layer (Repository Layer)

This layer handles database operations.

Responsibilities

• Performs CRUD operations

• Maps Java objects to database tables

• Interacts with database

Technologies

• Spring Data JPA

• Hibernate

• R2DBC

Common Annotations

• @Repository

• JpaRepository

• CrudRepository

• @Entity

• @Id

• @Table

6. Database Layer

This layer stores actual data.

Types of Databases

• Relational databases

  • MySQL

  • PostgreSQL

  • Oracle

  • SQL Server

• NoSQL databases

  • MongoDB

  • Cassandra

  • Firebase

7. Spring Boot Flow

Step 1

Client sends request

Step 2

Controller receives request

Step 3

Service layer processes logic

Step 4

Repository interacts with database

Step 5

Response is returned as JSON

8. Spring Boot Actuator

Spring Boot provides Actuator for monitoring.

Features

• Health check

• Application metrics

• Environment details

• Memory and thread monitoring

• Custom endpoints

9. Conclusion

• Spring Boot architecture is layered and clean

• Each layer has a specific responsibility

• Helps build scalable and maintainable applications