layered-architecture

Prevent business logic from leaking into Spring Boot controllers by enforcing strict layer separation, keeping controllers strictly HTTP-only while moving all business logic into dedicated service classes that handle transactional boundaries.

Mapping entities to DTOs in a layered Spring Boot architecture should be handled by dedicated mapper classes rather than directly in controllers or services. This approach enforces strict layer boundaries and ensures safe data transformation across presentation and data layers.

In a Spring Boot layered architecture, @Transactional annotations belong on service classes rather than controllers or repositories. This placement ensures business logic manages transactional boundaries correctly while maintaining clean separation between presentation and data access layers.

Structure a new Spring Boot module by enforcing strict layer separation across controllers, services, repositories, DTOs, mappers, and configuration packages. Ensure one service per aggregate, use constructor injection, and add tests for layer boundaries to validate structural integrity.

This layered architecture approach works for both modifying existing Spring Boot classes and generating new project scaffolding. It applies documented rules and examples to enforce consistent project structure, clear responsibilities, and safe mappings across all generated or modified components.