Task Tracker API

A beginner-level Spring Boot REST API for managing tasks (create, read, update, delete).

This project is meant to show clean backend structure and core API concepts in a simple way.

What This Project Does

The API lets a client:

• create a task
• view all tasks
• view one task by ID
• update a task
• delete a task

Each task has fields like title, description, status, and due date.

Tech Stack

• Java + Spring Boot
• PostgreSQL
• Spring Data JPA (Hibernate)
• DTO pattern
• Bean Validation (@Valid, @NotBlank, @Size, @FutureOrPresent)
• Global exception handling with @ControllerAdvice

Project Structure

src/main/java/com/example/tasktracker
├── controller   # handles HTTP requests/responses
├── service      # business logic
├── repository   # database access (JPA)
├── model        # entity classes (database tables)
├── dto          # request/response objects
└── exception    # custom exceptions + global error handler

Why This Structure?

This layered structure is used so each part has one clear job:

• Separation of concerns: controller, service, and database logic are not mixed together.
• Cleaner code: easier to read, debug, and test.
• Scalable design: this is the same style used in many real backend projects.

Key Concepts (Simple Version)

• Controller: receives API requests (GET, POST, etc.) and returns responses.
• Service: contains the application rules (for example, duplicate title checks).
• Repository: talks to the database using Spring Data JPA methods.
• DTOs: objects used for API input/output.
  We use DTOs instead of entities so API models stay clean and independent from database models.

Request Flow

Client → Controller → Service → Repository → Database → Response

Validation and Error Handling

• Validation is applied to incoming request bodies using @Valid.
• Field rules like @NotBlank and @Size prevent bad input.
• A global handler (@ControllerAdvice) returns consistent API errors.

Common responses:

• 400 Bad Request: validation failed (invalid input)
• 404 Not Found: task ID does not exist
• 409 Conflict: duplicate task title

Setup Instructions

1) Start PostgreSQL with Docker

docker run --name task-tracker-db \
  -e POSTGRES_USER=postgres \
  -e POSTGRES_PASSWORD=postgres \
  -e POSTGRES_DB=task_tracker \
  -p 5432:5432 \
  -d postgres:16

2) Start the Spring Boot app

From the project root:

./mvnw spring-boot:run

The API runs at: http://localhost:8080

API Endpoints

• POST /api/tasks
• GET /api/tasks
• GET /api/tasks/{id}
• PUT /api/tasks/{id}
• DELETE /api/tasks/{id}

Example Request Body (Create/Update)

{
  "title": "Study Spring Boot",
  "description": "Review controller and service layers",
  "status": "TODO",
  "dueDate": "2026-05-01"
}

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This project is focused on learning backend fundamentals with clean architecture and practical REST API patterns.