Spring Boot Flashcard Application

A Spring Boot application for flashcard functionality with user authentication and money transfer features.

Features

• User authentication and authorization with Spring Security
• User account management with profile information
• User connections and relationships
• Money transfer system with fee tracking
• Thymeleaf-based web interface
• MySQL database integration
• JPA/Hibernate data persistence

Technology Stack

• Java: 17
• Spring Boot: 3.0.4
• Spring Security: Authentication and authorization
• Spring Data JPA: Data persistence
• Hibernate: ORM
• Thymeleaf: Template engine
• MySQL: Database (production)
• H2: In-memory database (testing)
• Lombok: Boilerplate code reduction
• Maven: Build tool
• JaCoCo: Code coverage

Prerequisites

• Java 17 or higher
• Maven 3.6+ (or use included Maven wrapper)
• MySQL 8.0+ (for running the application)
• Git

Note: MySQL is not required for running tests. Tests use an in-memory H2 database automatically.

Getting Started

1. Clone the Repository

git clone <repository-url>
cd java-springboot-flashcard

2. Database Setup

Create a MySQL database and user:

CREATE DATABASE flashcard;
CREATE USER 'flashcard'@'localhost' IDENTIFIED BY 'your_password';
GRANT ALL PRIVILEGES ON flashcard.* TO 'flashcard'@'localhost';
FLUSH PRIVILEGES;

Ensure MySQL is running on port 3380, or update the port in src/main/resources/application.yaml.

3. Configure Environment

Set the database password as an environment variable:

export FLASHCARD_DB_PASSWORD=your_password

4. Build the Application

./mvnw clean package

5. Run the Application

./mvnw spring-boot:run

The application will start and automatically create/update database tables based on JPA entities.

Development

Running Tests

Tests use an in-memory H2 database and do not require MySQL to be running:

./mvnw test

Note: Tests automatically use the test profile which is configured to use H2 instead of MySQL. No database setup or environment variables are required for testing.

Run Specific Test

./mvnw test -Dtest=YourTestClassName
./mvnw test -Dtest=YourTestClassName#specificTestMethod

Code Coverage

Generate coverage report:

./mvnw test jacoco:report

View report at: target/site/jacoco/index.html

Hot Reload

The application includes Spring Boot DevTools for automatic restart during development. Simply make changes to your code and the application will restart automatically.

Project Structure

src/
├── main/
│   ├── java/com/ericbouchut/java/springboot/flashcard/
│   │   ├── Application.java              # Main application entry point
│   │   ├── config/                       # Configuration classes
│   │   │   ├── SecurityConfiguratio.java # Spring Security setup
│   │   │   └── MvcConfig.java            # MVC configuration
│   │   ├── model/                        # JPA entities
│   │   │   ├── User.java                 # User entity
│   │   │   ├── UserAccount.java          # User account details
│   │   │   ├── Link.java                 # User connections
│   │   │   └── Transfer.java             # Money transfers
│   │   ├── service/                      # Business logic
│   │   ├── repository/                   # Data access layer
│   │   ├── controller/                   # Web controllers
│   │   └── dto/                          # Data transfer objects
│   └── resources/
│       ├── application.yaml              # Application configuration
│       └── templates/                    # Thymeleaf templates
└── test/
    ├── java/                             # Test classes
    └── resources/
        └── application-test.yaml         # Test configuration (H2 database)

Configuration

Application Properties

Production (src/main/resources/application.yaml):

• Database: MySQL connection on localhost:3380
• JPA: Hibernate with auto DDL update
• Logging: DEBUG level for Hibernate SQL and application code
• Thymeleaf: Template caching disabled for development

Test (src/test/resources/application-test.yaml):

• Database: H2 in-memory database (no setup required)
• JPA: Hibernate with create-drop DDL (clean database for each test run)
• Logging: Same as production for debugging test issues

Environment Variables

• FLASHCARD_DB_PASSWORD: MySQL database password (required for running the application, not needed for tests)

Domain Model

User

• Authentication and profile information
• Email (unique), password, first name, last name
• Connected to UserAccount (one-to-one)
• Connected to Links (many-to-many)

UserAccount

• Additional account information for users
• One-to-one relationship with User

Link

• Represents connections between two users
• Many-to-one relationships with User

Transfer

• Money transfers between users
• Tracks amount before and after fees
• Includes timestamp and from/to users

Testing

Test Infrastructure

The project uses:

• Spring Boot Test: Integration testing framework
• Spring Security Test: Security testing support
• H2 Database: In-memory database for tests (configured via @ActiveProfiles("test"))
• JaCoCo: Code coverage reports

Test Configuration

Tests automatically use a separate configuration profile:

• Profile: test (activated via @ActiveProfiles("test") in test classes)
• Database: H2 in-memory (no external database required)
• Schema: Created and dropped automatically for each test run

Coverage Exclusions

JaCoCo excludes the following from coverage reports:

• Application entry points (*Application.class)
• Exception classes (**/exception/**/*)
• DTOs (**/dto/**/*, **/*DTO.class)

Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the terms specified in the LICENSE file.

Resources

• Spring Boot Documentation
• Spring Security Documentation
• Spring Data JPA Documentation
• Thymeleaf Documentation