Tip: Organizing packages for a clean Spring app

“A tidy codebase is like a well-organized toolbox—find what you need in seconds, not minutes!” 🔧✨

Keeping your Spring Boot project’s packages clean and intuitive pays dividends as your app grows. Here’s a monkey-proof guide:

📂 1. Layer-Based vs. Feature-Based Structure

Layer-Based (Classic)

arduinoCopyEditcom.example.demo
├── controller
├── service
├── repository
├── model
└── config

• Pros: Everybody knows where to look.
• Cons: Can become unwieldy in large apps—too many classes in each layer.

Feature-Based (Modular)

pgsqlCopyEditcom.example.demo
├── user
│   ├── UserController.java
│   ├── UserService.java
│   ├── UserRepository.java
│   └── User.java
├── order
│   ├── OrderController.java
│   ├── OrderService.java
│   └── OrderRepository.java
└── common
    ├── config
    └── util

• Pros: Group everything by feature; high cohesion.
• Cons: New team members need to learn feature names.

🔍 2. Sample Package Declarations

javaCopyEdit// Layer-based example
package com.example.demo.controller;
@RestController
public class ProductController { … }

// Feature-based example
package com.example.demo.order;
@RestController
public class OrderController { … }

🛠️ 3. Core Packages to Include

• config
  Classes for security, Swagger, CORS, data sources.
• controller or feature/…
  Your REST endpoints.
• service
  Business logic—keep it stateless and testable.
• repository
  Spring Data interfaces for DB access.
• model or entity
  JPA entities or DTO classes.
• util or common
  Shared helpers, constants, exceptions.

💡 4. Bonus Tips

• Keep package names short and meaningful.
• Avoid deep nesting, no more than 3 levels.
• Use @ComponentScan basePackages if you move your main class: javaCopyEdit@SpringBootApplication(scanBasePackages = "com.example.demo") public class DemoApplication { … }
• Re-evaluate structure periodically as new features land.