SpringBoot-Notes-Api — Backend

A RESTful backend for managing folder-based notes with reusable tags, built with Spring Boot and Spring Data JPA.

Overview

This backend provides a cleanly designed REST API for folder-based notes with reusable tags, featuring:

• Full CRUD (Create, Read, Update, Delete)
• Partial updates (PATCH) and full replacement (PUT)
• Clear, conventional HTTP status codes
• Centralized error handling
• Auto-managed createdAt timestamps
• In-memory H2 database for easy development

---

Tech Stack

• Java 17+
• Spring Boot
• Spring Web
• Spring Data JPA (declarative transactions with @Transactional)
• H2 Database (dev)
• Jackson (JSON)

Design choices:

• REST semantics (PUT vs PATCH)
• Service-layer invariants (validation + business rules)

---

Project Structure

src/main/java/com/practice/notes/

NotesApplication.java
├── controller/
│   └── NoteController.java
│   └── FolderController.java
├── exceptions/
│   ├── BadRequestException.java
│   ├── NotFoundException.java
│   └── GlobalExceptionHandler.java
├── model/
│   └── Note.java
│   └── Folder.java
│   └── Tag.java
├── repository/
│   └── NoteRepository.java
│   └── FolderRepository.java
│   └── TagRepository.java
└── service/
    └── NoteService.java
    └── FolderService.java

src/main/resources/

application.properties

---

Data Model

Note

Field	Description
id	Auto-generated primary key
title	Required
content	Required
folder	Each note belongs to a folder
tags	Many-to-many tags (stored separately)
createdAt	Automatically set on creation
pinned	Pin state

Folder

Field	Description
id	Auto-generated primary key
name	Required

Tag

Field	Description
id	Auto-generated primary key
name	Unique tag name

Tag behavior

• Tags are created implicitly when notes are created or updated.
• Tags do not have an independent lifecycle or controller.
• Tag resolution is centralized in NoteService.

---

API Endpoints

NoteController

Method	Endpoint	Description
POST	/folders/{folderId}/notes	Create a note in a folder
GET	/notes/{id}	Get note by ID
GET	/folders/{folderId}/notes	Get notes by folder
PATCH	/notes/{id}	Partial update
PUT	/notes/{id}	Full replace
PATCH	/notes/{id}/pin	Pin a note
DELETE	/notes/{id}	Delete a note

Notes:

• Folder ID comes from the URL path, not the request body.
• Controllers stay thin; service layer enforces invariants.

FolderController

Method	Endpoint	Description
POST	/folders	Create a folder
GET	/folders	Get all folders
DELETE	/folders/{id}	Delete a folder

---

Error Handling

The API returns errors in a consistent format using custom exceptions and a global handler. Errors are thrown from the service layer so controllers remain lightweight.

Example: 404 — Not Found

{
  "error": "NOT_FOUND",
  "message": "Note not found"
}

Example: 400 — Bad Request

{
  "error": "BAD_REQUEST",
  "message": "Title is required"
}

---

Database

• Uses H2 in-memory database for development
• Schema auto-generated via JPA
• Data resets on app restart

---

Running the Application

1. Clone the repository
   git clone https://github.com/YOUR_USERNAME/SpringBoot-Notes-Api.git

2. Run the application

   mvn spring-boot:run
   

3. Access the API:
   http://localhost:8080

---

Why This Project Matters

• Models real relationships (folders, notes, tags) instead of flat CRUD.
• Enforces rules in services, not controllers.
• Avoids unnecessary controllers (tags are managed implicitly).
• Keeps API intent clear with REST semantics.