Roommate System

A Spring Boot REST API for managing shared expenses between roommates. Track apartments, expenses, and payments all in one place.

What it does

This is a backend service that helps roommates split bills and track who's paid what. You can create apartments, add expenses (like rent, utilities, groceries), and record payments. The API uses JWT authentication so each user only sees their own data.

Tech stack

• Spring Boot 4.0.1 - Main framework
• PostgreSQL - Database
• Spring Security - Authentication and authorization
• JWT - Token-based auth
• Maven - Dependency management

Getting started

Prerequisites

• Java 17 or higher
• Maven
• PostgreSQL (or use Docker Compose)

Setup

1. Clone the repo:

git clone <your-repo-url>
cd p3project

2. Start PostgreSQL with Docker Compose:

docker-compose up -d

Or set up PostgreSQL manually and update application.properties with your database credentials.

3. The database schema will be created automatically from src/main/resources/schema.sql when you first run the app.

4. Run the application:

./mvnw spring-boot:run

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

API endpoints

Authentication

• POST /api/users/register - Create a new account
• POST /api/users/login - Login and get a JWT token

Apartments

• GET /api/apartments - Get all apartments for the current user
• GET /api/apartments/{id} - Get apartment by ID
• POST /api/apartments - Create a new apartment (requires auth)
• PUT /api/apartments/{id} - Update apartment (requires auth)
• DELETE /api/apartments/{id} - Delete apartment (requires auth)
• POST /api/apartments/{apartmentId}/members/{userId} - Add a member to an apartment

Expenses

• GET /api/expenses/apartment/{apartmentId} - Get all expenses for an apartment
• POST /api/expenses - Create a new expense (requires auth)

Payments

• GET /api/payments/expense/{expenseId} - Get all payments for an expense
• POST /api/payments - Record a payment (requires auth)

Admin

• GET /api/admin/users - Get all users (admin only)
• DELETE /api/admin/users/{id} - Delete a user (admin only)

Authentication

Most endpoints require a JWT token. After logging in, you'll get a token that you need to include in the Authorization header:

Authorization: Bearer <your-token-here>

Tokens expire after 24 hours by default (configurable in application.properties).

Configuration

Edit src/main/resources/application.properties to change:

• Database connection details
• JWT secret and expiration time
• Connection pool settings

Database schema

The app uses these main tables:

• users - User accounts
• apartments - Apartment listings
• apartment_members - Links users to apartments (many-to-many)
• expenses - Bills/expenses tied to apartments
• payments - Individual payments toward expenses

Testing

There's a test file at src/main/resources/api.http with example requests you can use with REST Client extensions in VS Code or IntelliJ.

Notes

• Passwords are hashed using Spring Security's BCrypt
• Users can only access apartments they're members of
• Expenses are tied to apartments, not individual users
• The first user you create will have the USER role by default