Book-Library-API

A RESTful API for managing books and authors, built with Java and Spring Boot. The API provides CRUD operations for books and authors and manages the relationship between them.

Built With

• Java
• Spring Boot
• Spring Web
• Spring Data JPA
• Hibernate
• PostgreSQL
• Maven
• Lombok
• Bean Validation

Features

• Author CRUD
• Book CRUD
• Author–Book relationship
• Request validation
• Partial updates with PATCH
• Global exception handling
• Business rule validation
• PostgreSQL persistence

API Endpoints

Authors

Method	Endpoint	Description
GET	/authors	Get all authors
GET	/authors/{id}	Get an author
POST	/authors	Create an author
PATCH	/authors/{id}	Update an author
DELETE	/authors/{id}	Delete an author

Books

Method	Endpoint	Description
GET	/books	Get all books
GET	/books/{isbn}	Get a book
POST	/books	Create a book
PATCH	/books/{isbn}	Update a book
DELETE	/books/{isbn}	Delete a book

Project Structure

The project follows a layered architecture:

src/
├── main/
│   ├── java/
│   │   └── com.marouane.library/
│   │       ├── controller/
│   │       ├── service/
│   │       ├── repository/
│   │       ├── entity/
│   │       ├── dto/
│   │       ├── command/
│   │       ├── mapper/
│   │       ├── exception/
│   │       └── projections/
│   │
│   └── resources/
│       └── application.properties
│
└── test/

Main Layers

• Controller : Handles HTTP requests and responses.
• Mapper : Converts between DTOs, Commands, and Entities.
• DTO / Command : Transfers data between the API and application layers.
• Service : Contains business logic and business rules.
• Repository : Handles database access using Spring Data JPA.
• Entity : Represents the database model.
• Exception : Contains application exceptions and global exception handling.

Database Configuration

The application uses PostgreSQL.

1. Create the Database

Create the PostgreSQL database:

CREATE DATABASE library_db;

2. Configure Environment Variables

Create a .env file in the project root:

DB_URL=jdbc:postgresql://localhost:5432/library_db
DB_USERNAME=postgres
DB_PASSWORD=your_password

Replace the database username and password with your own PostgreSQL credentials.

How to Run

Requirements

• Java 21
• PostgreSQL
• Maven

1. Clone the repository

git clone https://github.com/marouaneaddou/Book-Library-API.git
cd Book-Library-API

2 Configure PostgreSQL

Make sure PostgreSQL is running and the database has been created.`

Configure your environment variables with the PostgreSQL connection details.

3. Start the Application

Using Maven Wrapper:

./mvnw spring-boot:run

On Windows:

mvnw.cmd spring-boot:run

Or using Maven:

mvn spring-boot:run

The API will be available at:

http://localhost:8080

Future Improvements

Possible future improvements:

• Authentication
• Authorization and role-based access control
• Pagination
• Filtering and sorting
• Book search
• OpenAPI / Swagger documentation
• Docker support

Purpose

This project was built to practice Java backend development with Spring Boot and apply REST API design, layered architecture, database persistence, validation, and business logic separation in a practical project.