📦 Product API - Spring Boot & PostgreSQL

This is a practical project of a RESTful API built with Java and Spring Boot, connected to a PostgreSQL relational database, and secured with JWT authentication via Spring Security.

🌱 About this project: This repository marks my first hands-on experience with the Spring Boot framework. The main goal was to understand the basics of data persistence (CRUD) using JPA and Hibernate, and I later expanded it to include authentication and authorization with Spring Security and JWT. I am using this project as a study lab and I intend to dive deeper and deeper into the Spring ecosystem!

🛠️ Technologies Used

• Java
• Spring Boot (Web, Data JPA, Security)
• Spring Security (Authentication & Authorization)
• JWT (JSON Web Token, via jjwt)
• PostgreSQL (Database)
• Hibernate (ORM)
• BCrypt (Password hashing)
• Insomnia (For API testing and sending JSON requests)

🚀 How to run the project locally

Prerequisites

Before you begin, you will need to have the following installed on your machine:

• Java JDK (version 17 or higher recommended)
• PostgreSQL
• An IDE of your choice (IntelliJ IDEA, Eclipse, VS Code)

Step by Step

1. Clone this repository:

   git clone https://github.com/andynnnfw/spring-rest-api-postgres.git

2. Configure the Database: Open pgAdmin or your PostgreSQL terminal and create a database named meubanco:

   CREATE DATABASE meubanco;

3. Configure the credentials: Open the src/main/resources/application.properties file and change the username and password to your local PostgreSQL credentials:

   spring.datasource.username=your_username_here
   spring.datasource.password=your_password_here

4. Start the application: Run the project through your IDE or by using Maven. The API will be running at http://localhost:8080.

🔐 Authentication

This API uses JWT (JSON Web Token) for stateless authentication. Passwords are hashed with BCrypt before being stored in the database, and most routes require a valid token to be accessed — except for the /auth/** endpoints, which are public.

Register

• Route: POST /auth/register
• Description: Creates a new user with an encrypted password.
• Request Body (JSON):

  {
    "username": "andyn",
    "password": "yourpassword"
  }

• Success Response: 200 OK

Login

• Route: POST /auth/login
• Description: Validates the credentials and returns a JWT token to be used in protected routes.
• Request Body (JSON):

  {
    "username": "andyn",
    "password": "yourpassword"
  }

• Success Response: 200 OK

  {
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
  }

• Error Response: 401 Unauthorized if credentials are invalid.

Using the token

For protected routes, include the token in the Authorization header:

Authorization: Bearer <your_token_here>

📍 API Endpoints

Below are the available routes in the application:

List Products

• Route: GET /api/produtos
• Description: Returns a list of all products registered in the database.
• Success Response: 200 OK

Get Product by ID

• Route: GET /api/produtos/{id}
• Description: Returns a single product by its ID.
• Success Response: 200 OK
• Error Response: 404 Not Found if the product doesn't exist.

Create Product

• Route: POST /api/produtos
• Description: Saves a new product in the database.
• How to test: During development, I used Insomnia to test this endpoint, sending the product structure in JSON format through the request Body.
• Request Body (JSON):

  {
    "nome": "chocolati",
    "preco": 6.70
  }

• Success Response: 200 OK or 201 Created

Delete Product

• Route: DELETE /api/produtos/{id}
• Description: Removes a product from the database by its ID.
• Success Response: 204 No Content
• Error Response: 404 Not Found if the product doesn't exist.

⚠️ Error Handling

The API has a global exception handler that returns structured error responses instead of default stack traces, for example:

{
  "timestamp": "2026-09-17T12:00:00",
  "status": 404,
  "error": "recurso nao encontrado",
  "message": "produto com ID: 99 nao encontrado"
}