SpringBootWebProject

Backend REST API built with Spring Boot 3.0, Java 17, and JPA/Hibernate

This project was developed as an academic exercise (see the Project Specification), focusing on backend concepts and API development.

Overview

• Implements CRUD operations for users, orders, categories, and products via REST endpoints.
• Uses an in-memory H2 database for easy testing.
• Business logic for order subtotals and totals encapsulated inside entities.
• Centralized error handling with custom exceptions.

Front-end: None. All GET, POST, PUT, and DELETE requests were tested using Postman.

Technologies and Tools

• Java 17
• Spring Boot 3.x (Web, Data JPA)
• JPA/Hibernate
• H2 Database (in-memory, test profile)
• Maven
• JUnit 5
• Postman (manual testing)

Key Concepts and Skills

• Project Setup: Scaffolded via Spring Initializr and configured dependencies in pom.xml.

• Data Modeling: JPA entities and relationships:

  • Many-to-Many (Product ↔ Category)
  • One-to-Many (User → Order)
  • One-to-One (Order ↔ Payment)

• Composite Key: OrderItem with @Embeddable and @EmbeddedId.

• Layered Architecture: Controllers (Resources), Services, and Repositories.

• Spring Profiles: Configured a test profile using H2 (application-test.properties).

• Data Seeding: Automatically populates the database on startup in the test profile.

• Exception Handling: Custom ResourceNotFoundException, DatabaseException, and a global handler.

• Date/Time Handling: Used Instant with ISO 8601 formatting in JSON.

• Business Logic in Entities: Subtotal in OrderItem and total in Order.

• Lazy vs Eager Loading: Avoided serialization issues with @JsonIgnore.

Commit History Overview

1. Initial Setup: Created Maven project and added core dependencies.
2. User Entity & H2 Configuration: Defined User entity and set up H2 test profile.
3. User CRUD: Implemented repository, service, and controller; added data seeding.
4. Order Entity & OrderStatus: Added Order entity with enum status and relationships.
5. Product & Category: Modeled many-to-many relationship between products and categories.
6. OrderItem & Composite Key: Implemented composite key for order items and subtotal logic.
7. Payment Entity: Added one-to-one payment entity with cascade operations.
8. Error Handling: Introduced custom exceptions and a global exception handler.
9. Final Adjustments: Tested all endpoints using Postman.

Running the Application Locally

1. Clone the repo:

   git clone https://github.com/enzoconsulo/JAVA.SpringBoot.WebProject-jpa.git
   cd JAVA.SpringBoot.WebProject-jpa

2. Build with Maven:

   mvn clean install

3. Run with the test profile (H2):

   mvn spring-boot:run -Dspring-boot.run.profiles=test

4. Access the H2 Console:

   • URL: http://localhost:8080/h2-console
   • JDBC URL: jdbc:h2:mem:testdb
   • User: sa, Password: (leave blank)

API Endpoints (prefix /api)

• /users — CRUD operations for users
• /orders — CRUD operations for orders
• /categories — CRUD operations for categories
• /products — CRUD operations for products

Project Structure

src/
 ├─ main/
 │   ├─ java/com/enzoccs/
 │   │   ├─ controller/
 │   │   ├─ model/
 │   │   ├─ repository/
 │   │   ├─ service/
 │   │   └─ exceptions/
 │   └─ resources/
 │       ├─ application.properties
 │       └─ application-test.properties
 └─ test/
     └─ SpringBootWebProjectApplicationTests.java
pom.xml
README.txt
EnunciadoDoProjeto.pdf

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Developed by a Computer Engineering student to deepen backend skills with Spring Boot.