Mapstruct mapper to alliviate workload of implementing jpa relationships

Context

In a recent project, I separated domain models from persistence entities (distinct POJOs for each). The goal is to keep database concerns out of the domain layer so the domain remains clean, testable, and persistence-agnostic. On the entity side, we can still leverage the essential JPA annotations that make it straightforward and productive.

I used MapStruct to map between domain and entity POJOs with minimal boilerplate. Because MapStruct traverses the object graph via getters/setters, it also makes it easy to (re)establish or reset persistence relationships as needed during mapping.

This separation—distinct domain and entity models—continues to prove its value: it enforces clear boundaries, reduces coupling to JPA, and simplifies testing. I’ll publish a small demo app to illustrate this approach and the mapping patterns.

---

Why this architecture helps (at a glance)

• Clean domain: No JPA annotations or persistence abstractions in domain code.

• Focused entities: JPA annotations live only where they belong—on the persistence side.

• Easy mapping: MapStruct handles object graph traversal and relationship wiring with little code.

• Testability: Domain tests don’t require JPA or database setup.

• Flexibility: Freedom to evolve persistence or domain independently.