My Java DB App

This is a Spring Boot application that connects to a MySQL database using JPA. The project is containerized using Docker and can be run with Docker Compose. It includes REST APIs for managing users and orders.

Prerequisites

• Docker and Docker Compose installed on your system.
• Java 17 installed if running locally.
• Maven installed for building the project.

Project Structure

02-my-java-db-app/
├── all_restart.sh            # Script to rebuild and restart the full stack
├── app_restart.sh            # Script to rebuild and restart only the application
├── docker-compose.all.yaml   # Docker Compose file for the full stack
├── docker-compose.app.yaml   # Docker Compose file for the application
├── docker-compose.db.yaml    # Docker Compose file for the database
├── Dockerfile.app            # Dockerfile for building the application container
├── Dockerfile.db             # Dockerfile for building the database container
├── pom.xml                   # Maven configuration file
├── src/                      # Source code for the application
│   ├── main/
│   │   ├── java/             # Java source files
│   │   └── resources/        # Application properties, schema, and data files
│   └── test/                 # Unit tests
├── dbdata/                   # Persistent database storage
└── docs/                     # Documentation files

How to Run

Start the Database

To start the MySQL database container:

docker-compose -f docker-compose.db.yaml up -d

Start the Application

To build and start the application container:

docker-compose -f docker-compose.app.yaml build
docker-compose -f docker-compose.app.yaml up -d

Stop the Containers

To stop the application and database containers:

docker-compose -f docker-compose.app.yaml down
docker-compose -f docker-compose.db.yaml down

Start or Stop Full Stack

To start or stop the full stack (application and database):

docker-compose -f docker-compose.all.yaml up -d
docker-compose -f docker-compose.all.yaml down

Rebuild and Restart

To rebuild and restart the full stack:

./all_restart.sh

To rebuild and restart only the application:

./app_restart.sh

Configuration

The application uses the following environment variables for database configuration:

• SPRING_DATASOURCE_URL: JDBC URL for the database (default: jdbc:mysql://db:3306/mydatabase)
• SPRING_DATASOURCE_USERNAME: Database username (default: myuser)
• SPRING_DATASOURCE_PASSWORD: Database password (default: mypassword)

These variables are defined in the docker-compose.app.yaml file.

API Endpoints

The application exposes the following REST API endpoints:

Health Check

curl http://localhost:8080/api/healthcheck

Users API

• Get all users:

  curl http://localhost:8080/api/users

• Create a new user:

  curl -X POST -H "Content-Type: application/json" -d '{"name":"John","email":"john@example.com"}' http://localhost:8080/api/users

Orders API

• Get all orders:

  curl http://localhost:8080/api/orders

• Create a new order:

  curl -X POST -H "Content-Type: application/json" -d '{"userId":1,"productName":"Tablet","amount":500.00}' http://localhost:8080/api/orders

Database

The database schema and initial data are defined in the following files:

• src/main/resources/schema.sql: Defines the users and orders tables.
• src/main/resources/data.sql: Inserts initial data into the users and orders tables.

To manually inspect the database, connect to the MySQL container:

docker exec -it my-java-db-app-db-1 mysql -u myuser -pmypassword mydatabase

Run the following SQL commands:

SHOW TABLES;
SELECT * FROM users;
SELECT * FROM orders;

Testing

To run the unit tests:

mvn test

Troubleshooting

• If the application fails to start, check the logs:

  docker logs <container_id>

• Ensure the database container is running and accessible.
• If the database schema or data is not initialized, ensure schema.sql and data.sql are in the src/main/resources directory and that the application.properties file has the correct configuration:

  spring.datasource.initialization-mode=always
  spring.jpa.defer-datasource-initialization=true

License

This project is licensed under the MIT License.