Spring Boot Starter

🎯 About

Simple and scalable starter-kit to build powerful and organized REST projects with Spring Boot.

✨ Features

• Logging
• IP-based Rate Limiting using TokenBucket
• En/decrypt ENV variables
• Secure APIs using HTTPS
• Exception Handling
• Organize custom error codes for consistency, clarity, and easy debugging

🚀 Tech Stack

• JDK: 21
• Maven: 3.9.9
• Spring: 3.5.x
  • Spring Boot
  • Spring Web
  • Spring Validation
  • Spring Security with JWT
  • Spring Data JPA
• MySQL: 8.4
• Lombok: 1.18

Dependencies

• Spring Boot Modules:
  • Spring Web (for REST APIs)
  • Spring Validation (for input validation)
  • Spring Security (with JWT for authentication)
  • Spring Data JPA (with MySQL for datasource)
• Other Libs:
  • Lombok (simplify development with annotations)
  • Log4j2 (for high-performance logging)
  • SpringFox (generate Swagger API documentation and UI)
  • bucket4j (for IP-based Rate Limiting)
  • Jasypt (en/decrypt sensitive environment variables)

⚙️ Running the Service

Development Setup

Run the application locally, pass jasypt.encryptor.password as Spring Boot Property.

Use GitBash if you are on Windows.

mvn clean spring-boot:run -Dspring-boot.run.arguments="--jasypt.encryptor.password=encryption-password"

Note: When accessing these URLs in development, you might see certificate warnings in your browser due to self-signed certificates. This is expected, and you can proceed safely for development purposes.

🔒 Encryption with Jasypt

Jasypt ensures sensitive configuration values like database credentials and API keys are securely encrypted.

Workflow

1. Add properties to be encrypted in application.properties with DEC(value-here)
2. Run the provided encrypt command to replace all DEC(...) values with their encrypted form

Commands

Encrypt Properties

Use GitBash if you are on Windows.

mvn jasypt:encrypt -Djasypt.plugin.path=file:src/main/resources/application-dev.properties -Djasypt.encryptor.password=encryption-password

Decrypt Properties

Decrypt credentials that are wrapped with ENC(value) in application.properties file.

Use GitBash if you are on Windows.

mvn jasypt:decrypt -Djasypt.plugin.path=file:src/main/resources/application-dev.properties -Djasypt.encryptor.password=encryption-password

Which would output the decrypted contents to the screen, rather than editing the file in place.

Run packaged Jar with encrypted properties

Run the Spring Boot application by passing the private key password as VM arguments in the command prompt like this:

java -jar target/your-application.jar -Djasypt.encryptor.password=encryption-password

📋 Swagger

• Swagger API Documentation - JSON
• Swagger API Documentation - YAML
• Swagger UI

Swagger provides a user-friendly interface for interacting with your REST endpoints during development.

Structure

Package Organization

Structured the app with layered architecture to be modular, testable and scalable. Can adjust base on specific project needs.

com.nyanmyohtet.springbootstarter
│
├── api/rest            // REST controllers
├── service             // Business logic
├── repository          // Data access logic (Spring Data JPA, etc.)
├── model               // Domain models/entities
├── dto                 // Data Transfer Objects
├── config              // Configuration classes (security, caching, etc.)
├── exception           // Custom exceptions and handlers
├── util                // Utility or helper classes
└── SpringBootApplication.java    // Main entry point

Layer Responsibilities

• Controller Layer: Handles incoming HTTP request and map them to services.
• Service Layer: Contains business logic, avoid placing logic in controller.
• Repository Layer: Manages database interactions, usually using Spring Data JPA.
• Model Layer: Defines the structure of the data.
• DTOs (Data Transfer Object): Defines data structure for communication between parties(e.g., client and server).

Configuration

The config package hold:

• application.properties, application-<profile>.properties: define externalized configurations.
• Security: Spring Security setup.
• Scheduler: Scheduler config.
• Custom beans: defines beans for service wiring, third-party libs, etc.

Exception Handling

• Place custom exceptions in exception package.
• use @RestControllerAdvise for centralized exception handling for REST endpoints.

Testing

• Place tests in src/test/java with the same package structure as main code.
• Use JUnit 5 for testing, MockMvc for controller tests and Mockito for mocking dependencies.