Introduction to Spring Boot

Welcome and Overview

• Course on Spring Boot by Amigos Code.
• Objectives:
  • Learn Spring Boot framework.
  • Build an API with 3 layers.
  • Connect to a real database.
  • Practical exercises provided.
  • Access to source code upon completion.
  • Community engagement via Facebook and Discord.
  • Additional resources on testing and other relevant topics available.

What is Spring Boot?

• Framework for building Java and Kotlin applications.
• Popular for backend and full-stack applications.
• Features:
  • Built-in modules for security, logging, database connectivity.
  • Production-ready, microservices, dependency injection.
  • Configuration and great community support.

Project Structure

• API will handle GET, POST, PUT, DELETE requests.
• Three layers: API, Service, Data Access.
• Use Spring Initializr to bootstrap the application.
• Maven, Java 15, Spring Boot version 2.4.1.
• Selected dependencies: Spring Web, Spring Data JPA, PostgreSQL driver.

Setup Instructions

• Spring Initializr: Configure project and dependencies.
• IDE: Recommended IntelliJ IDEA Ultimate Edition.
• Example project setup, folder structure explanation, and running the server.
• Initial example of RESTful API returning JSON data.

Building a Complete Application

Layers and Components

1. API Layer: Handles HTTP requests.
2. Service Layer: Business logic.
3. Data Access Layer: Communicates with the database.

Building API Components

• Create package structure and classes for StudentController, StudentService, and Student within IntelliJ.
• Learn and apply dependency injection.
• Annotations used: @RestController, @RequestMapping, @Service, @Autowired.
• Example static response replaced with data fetch from Service layer.
• Use of Spring Data JPA to connect to a PostgreSQL database.

Entity and Repository Setup

• Define entity (Student) using @Entity, @Table.
• Setup sequences for unique IDs with @Id and @GeneratedValue.
• Use PostgreSQL for database, settings in application.properties.
• Spring Data JPA Repository: Define interface extending JpaRepository.
• CRUD operations: findAll, save, deleteById, etc.

Adding Data and Configurations

• CommandLineRunner: Initialize the database with sample data.
• Demonstrate adding, fetching, and deleting data.

CRUD Operations for the API

GET Operation

• Fetch a list of students from the database.
• Use @GetMapping to define the endpoint.

POST Operation

• Add new students to the database.
• Use @PostMapping and request body to handle incoming data.
• Validate and save data, handle duplicates.

DELETE Operation

• @DeleteMapping to delete a student by ID.
• Verify existence and remove from the database safely.

PUT Operation

• Update existing student details using @PutMapping.
• Use @Transactional to handle database transactions.
• Business logic to update name, email only if valid.

Deploying Spring Boot Application

Packaging and Running the Application

• Use Maven to build the project: clean, validate, compile, test, package.
• Generate a jar file, demonstrate running it from the terminal.
• Override default port settings.

Testing and Further Learning

• Importance of testing; unit, integration, and mock testing.
• Recommendations for specialized course on testing.
• Mention of advanced courses on databases, Spring Data JPA, Postgres, etc.

Future Learning and Community

• Mention future tutorials on registration services, spring security.
• Encouragement to join the community on Facebook and Discord for continuous learning and support.