Spring Boot Tutorial 0/110 lessons ~6 min read Lesson 36“Production-grade backends”

Repository Pattern

The Repository pattern abstracts persistence behind an interface.

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Focus

2 guided sections

Practice signal

Examples included

Career prep

Foundation builder

Introduction

The Repository pattern abstracts persistence behind an interface. Spring Data ships repositories you extend; for domain-driven systems you can also hand-write repositories that hide JPA entirely.

Informative example

// Domain-driven flavour: hide JPA from the service
public interface OrderRepository {
  Optional<Order> byId(OrderId id);
  Order save(Order order);
  List<Order> activeFor(UserId userId);
}

// Adapter
@Repository
@RequiredArgsConstructor
class JpaOrderRepository implements OrderRepository {
  private final JpaOrderEntityRepository jpa;
  private final OrderMapper mapper;

  public Optional<Order> byId(OrderId id) {
    return jpa.findById(id.value()).map(mapper::toDomain);
  }
  // ...
}

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