Customer and Contact Management API

A REST API developed with Spring Boot for managing customers and their contacts, created as a technical challenge solution for Nubank.

🚀 Technologies Used

• Java 17
• Spring Boot 3.5.4
• Spring Data JPA
• PostgreSQL
• Maven
• Lombok
• MapStruct
• Bean Validation
• SpringDoc OpenAPI (Swagger)

📋 Features

Customers

• ✅ Create customer
• ✅ List all customers
• ✅ Update customer
• ✅ Delete customer
• ✅ List contacts for a specific customer

Contacts

• ✅ Create contact
• ✅ List all contacts
• ✅ Get contact by ID
• ✅ Update contact
• ✅ Delete contact

🗄️ Data Model

Customer

customers
├── id (BIGINT, PRIMARY KEY)
├── name (VARCHAR, NOT NULL)

Contact

contacts
├── id (BIGINT, PRIMARY KEY)
├── telephone (VARCHAR, NOT NULL)
├── email (VARCHAR, NOT NULL)
├── customer_id (BIGINT, FOREIGN KEY)

Relationship: A customer can have multiple contacts (One-to-Many)

🔧 Setup and Installation

Prerequisites

• Java 17+
• PostgreSQL
• Maven 3.6+

1. Clone the repository

git clone https://github.com/Mirian97/costumer-and-contact-api.git
cd costumer-and-contact-api

2. Setup the database

Create a PostgreSQL database named nubank_db:

CREATE DATABASE nubank_db;

3. Configure credentials

Edit the application.properties file if needed:

spring.datasource.url=jdbc:postgresql://localhost:5432/nubank_db
spring.datasource.username=postgres
spring.datasource.password=pass1234

4. Run the application

mvn spring-boot:run

The application will be available at: http://localhost:8080

📖 API Documentation

Swagger UI

Access the interactive documentation at: http://localhost:8080/swagger-ui.html

Endpoints

Customers

Method	Endpoint	Description
GET	/customers	List all customers
POST	/customers	Create a new customer
PUT	/customers/{customerId}	Update a customer
DELETE	/customers/{customerId}	Delete a customer
GET	/customers/{customerId}/contacts	List customer's contacts

Contacts

Method	Endpoint	Description
GET	/contacts	List all contacts
GET	/contacts/{contactId}	Get contact by ID
POST	/contacts	Create a new contact
PUT	/contacts/{contactId}	Update a contact
DELETE	/contacts/{contactId}	Delete a contact

✅ Validations

• Customer name: Required
• Contact telephone: Required
• Contact email: Required
• Customer ID (for contacts): Required

🛠️ Technical Features

• Automatic validation with Bean Validation
• Global exception handling with @RestControllerAdvice
• Automatic documentation with OpenAPI 3
• Object-relational mapping with JPA/Hibernate
• Cascade relationships for CRUD operations
• DTOs for layer separation

📊 Database Schema

The application uses Hibernate DDL auto-update mode, so tables will be created automatically on first run. The schema includes:

• customers table with auto-generated ID and name field
• contacts table with auto-generated ID, telephone, email, and foreign key to customer
• One-to-Many relationship between customers and contacts with cascade operations

🚀 Getting Started

1. Ensure PostgreSQL is running on your machine
2. Create the database nubank_db
3. Update database credentials in application.properties if necessary
4. Run mvn spring-boot:run
5. Access the Swagger documentation at http://localhost:8080/swagger-ui.html
6. Start making API calls!

📄 License

This project was developed as part of a technical challenge.