E-commerce Backend built with Java Spring Boot, MySQL, Spring Security & JWT

I built this project to deepen my understanding of how to develop a professional backend using Java Spring Boot. In my university courses, I learned Java, but not how to create production-ready REST APIs or implement role-based authentication with Spring Security and JWT. This project also helped me refresh my skills in designing relational databases with MySQL.

Complete Tech Stack

• Java 17+
• Spring Boot
• Spring Data JPA (Hibernate)
• Spring Security
• Spring Web
• JWT Authentication
• MySQL Database
• Maven
• Lombock
• Postman for API Testing
• Java Spring Boot Architecture (Controller -> Service -> Repository -> Model, Dto's )

Features Summary

• CRUD for Products and Categories
• Cart Management (each User has 1 cart and can add, remove and update items)
• Order Management and Checkout
• JWT-based Login and Authorization
• Role-Based API Security with Spring Security & JWT

Database Diagram (MySQL)

REST API endpoints

All endpoints are prefixed with /api/v1/

AuthController, /auth

Method	Endpoint	Description
POST	/login	Authenticate a user and return a JWT token.
POST	/logout	Invalidate user session / JWT token.

CartController, /carts

Method	Endpoint	Description
GET	/{cartId}/my-cart	Retrieve a user’s current cart.
DELETE	/{cartId}/clear	Remove all items from a cart.
GET	/{cartId}/cart/total-price	Calculate total price of items in a cart.

CartItemController, /cartItems

Method	Endpoint	Description
POST	/item/add?productId={id}&quantity={q}	Add a product to the cart.
DELETE	/cart/{cartId}/item/{itemId}/remove	Remove an item from a specific cart.
PUT	/cart/{cartId}/item/{itemId}/update?quantity={q}	Update item quantity in a cart.

CategoryController, /categories

Method	Endpoint	Description
GET	/all	Get all product categories.
POST	/add	Add a new category.
GET	/category/{id}/category	Get category by ID.
GET	/category/{name}/category	Get category by name.
PUT	/category/{id}/update	Update a category by ID.
DELETE	/category/{id}/delete	Delete a category by ID.

ImageController, /images

Method	Endpoint	Description
POST	/upload	Upload product images (MultipartFile + productId).
GET	/image/download/{imageId}	Download an image by ID.
PUT	/image/{imageId}/update	Update an existing image.
DELETE	/image/{imageId}/delete	Delete an image by ID.

OrderController, /orders

Method	Endpoint	Description
POST	/order?userId={id}	Create a new order for a user.
GET	/{orderId}/order	Get order details by order ID.
GET	/{userId}/order	Get all orders placed by a specific user.

ProductController, /products

Method	Endpoint	Description
GET	/all	Get all products.
GET	/product/{id}/product	Get product by ID.
GET	/products/{name}/products	Get products by name.
GET	/product/by-brand?brand={brand}	Get products by brand.
GET	/product/{category}/all/products	Get products by category.
GET	/products/by/brand-and-name?brand={b}&name={n}	Get products by brand and name.
GET	/products/by/category-and-brand?category={c}&brand={b}	Get products by category and brand.
GET	/product/count/by-brand/and-name?brand={b}&name={n}	Count products by brand and name.
POST	/add (ADMIN only)	Add a new product.
PUT	/product/{id}/update (ADMIN only)	Update an existing product.
DELETE	/product/{id}/delete (ADMIN only)	Delete a product.

UserController, /users

Method	Endpoint	Description
GET	/{userId}/user	Retrieve a user by ID.
POST	/create	Create a new user.
PUT	/{userId}/update	Update user details.
DELETE	/{userId}/delete	Delete a user.

Folder Structure

Reflection

This project helped me:

• Deeply understand the Spring Boot backend architecture.
• Build a fully functional REST API using best practices.
• Learn Spring Security and JWT authentication hands-on.
• Strengthen my understanding of JPA relationships and DTO patterns.
• Gain confidence in building real-world backend applications.

How to Run the Project

1. Clone repo
2. Update your resources/application.properties, example structure from my project:

spring.application.name=shoppingCartBackend

spring.datasource.url=jdbc:mysql://localhost:3306/shoppingdb
spring.datasource.username=shoppinguser
spring.datasource.password=password123

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect

##update = database is saved
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
##To show database in terminal
spring.jpa.properties.hibernate.format_sql=true

api.prefix=/api/v1

spring.servlet.multipart.max-file-size=5MB
spring.servlet.multipart.max-request-size=5MB

## 1 hour
auth.token.expirationInMils=3600000
auth.token.jwtSecret=YOUR_JWT_SECRET

3. Run the project

mvn spring-boot:run

4. Test the API using Postman