Spring Boot Introduction Lecture Notes

Overview

• Greetings and Introduction:
  • Course targets teaching everything about Spring Boot
  • Spring Boot is a popular framework for Java and Kotlin

Course Objectives

• Build an API with Three Layers:
  1. API layer
  2. Service layer (for business logic)
  3. Data access layer (to connect to a database)
• Practical exercises and certificate offered on the website
• Active community through Facebook and Discord groups

Importance of Spring Boot

• Highly in-demand framework for building backend and full-stack applications
• Integration with different modules:
  • Security
  • Logging
  • Database connections (Postgres, MongoDB, MySQL)
• Features include:
  • Production-ready
  • Dependency injection
  • Microservices support

Getting Started

• Spring Initializer:
  • Website to bootstrap Spring Boot applications
  • Options for Maven or Gradle and languages (Java/Kotlin/Groovy)
  • Selecting dependencies:
    • Spring Web (for web applications)
    • Spring Data JPA (for database connections)
    • PostgreSQL driver

Setting Up the Project

• IDE: Recommended IntelliJ IDEA (Ultimate or Community Edition)
• Opening the created project and configuring pom.xml.
• Running the application:
  • Initial error expected due to missing database connection.

Creating a Simple REST API

• Implemented basic REST API with a single endpoint returning "Hello World".
• Converting response to JSON automatically.
• Setting up a model class (e.g., Student) with attributes and behaviors:
  • Using features like @Entity, @Table, @GeneratedValue for JPA.

Building Layers

API Layer

• Separate controller class StudentController
• Structure to handle requests and return responses
• Request mapping to defined API endpoints

Service Layer

• Created StudentService class for business logic, such as handling data processing
• Using dependency injection to connect Controller and Service classes

Data Access Layer

• Defined StudentRepository interface extending JpaRepository
• Use of Spring Data JPA methods like findAll(), save(), etc.

Connecting to PostgreSQL Database

• Configuration in application.properties:
  • Database URL, username, password, JPA settings
• Creation of student database and granting privileges using SQL commands.
• Running application and confirming database connection established.

Data Management

• Auto-creation of tables in the database from entity models using Hibernate JPA.
• CRUD operations implemented for students, including:
  • Creating new students
  • Updating student information
  • Deleting students

Advanced Features

• Email validation during creation of students
• Transaction management during updates using @Transactional
• Error handling with meaningful messages for different scenarios

Testing

• Importance of testing frameworks and practices (TDD, Mocking)
• Testing API endpoints with tools like Postman or tools integrated in IntelliJ
• Recommended courses for deeper learning on testing practices.

Packaging and Deployment

• Building a JAR using Maven for deployment.
• Running multiple instances of the application on different ports.

Conclusion

• Invite for feedback on the course and what students want to see next.
• Mention of upcoming tutorials on Spring security and other advanced topics.
• Encouragement to join the community and check out additional courses available.

Additional Resources

• Links to courses on Spring Data JPA, Testing, Spring Full Stack
• Encouragement to engage with the code examples on GitHub