springboot-patterns_skill

Overview

This skill packages proven Spring Boot architecture patterns for building scalable, production-grade Java backends. It covers REST API structure, layered services, data access, caching, async processing, logging, and operational best practices. Use it to standardize controllers, services, repositories, error handling, and observability across projects.

How this skill works

The skill codifies patterns: thin REST controllers, transactional service layer, Spring Data repositories, DTOs with validation, and centralized exception handling. It includes examples for caching (@EnableCaching + @Cacheable/@CacheEvict), async tasks (@EnableAsync + @Async), request logging and rate-limiting filters, retry helpers for external calls, and observability recommendations (metrics, tracing, structured logs).

When to use it

• When building REST APIs with Spring MVC or WebFlux that need clear controller → service → repository separation
• When configuring Spring Data JPA repositories, pagination, sorting, and DTO mapping
• When adding caching, async processing, or background jobs for performance
• When centralizing validation, exception handling, and security-related filters
• When preparing an app for production: connection pools, metrics, tracing, and structured logs

Best practices

• Keep controllers thin: delegate business logic to services and map domain → DTOs at the edges
• Prefer constructor injection and annotate transactional boundaries in services (@Transactional)
• Use @Validated / JSR-380 annotations on request DTOs and a ControllerAdvice for consistent errors
• Make external calls resilient with retry/backoff and keep handlers idempotent for background jobs
• Enable observability (Micrometer, Prometheus/OTel) and structured logging; configure HikariCP for DB pools

Example use cases

• Designing a paginated REST endpoint that returns Page<T> using PageRequest and DTO mapping
• Adding caching for frequently read entities with @Cacheable and evicting on updates
• Offloading notifications or long-running tasks using @Async and CompletableFuture
• Implementing a rate-limiting filter that uses request.getRemoteAddr() with trusted proxy configuration
• Centralizing validation errors and access-denied responses via @ControllerAdvice