Provides and generates complete CRUD workflows for Spring Boot 3 services. Creates feature-focused architecture with Spring Data JPA aggregates, repositories, DTOs, controllers, and REST APIs. Validates domain invariants and transaction boundaries. Use when modeling Java backend services, REST API e

Spring Boot CRUD Patterns Overview Provides complete CRUD workflows for Spring Boot 3.5+ services using feature focused architecture. Creates and validates domain aggregates, JPA repositories, application services, and REST controllers with proper separation of concerns. Defer detailed code listings to reference files for progressive disclosure. When to Use Create REST endpoints for create/read/update/delete workflows backed by Spring Data JPA. Implement feature packages following DDD inspired architecture with aggregates, repositories, and application services. Define DTO records, request validation, and controller mappings for external clients. Diagnose CRUD regressions, repository contracts, or transaction boundaries in existing Spring Boot services. Trigger phrases: "implement Spring CRUD controller" , "create an endpoint" , "add database entity" , "refine feature based repository" , "map DTOs for JPA aggregate" , "add pagination to REST list endpoint" . Instructions Follow this streamlined workflow to deliver feature aligned CRUD services with explicit validation gates: 1. Establish Feature Structure Create feature/<name / directories with domain , application , presentation , and infrastructure subpackages. Validate : Verify directory structure matches the feature boundary before proceeding. 2. Define Domain Model Create entity classes with invariants enforced through factory methods ( create , update ). Keep domain logic framework free. Validate : Assert all invariants are covered by unit tests before advancing. 3. Expose Domain Ports Declare repository interfaces in domain/repository describing persistence contracts without implementation details. Validate : Confirm interface signatures match domain operations. 4. Provide Infrastructure Adapter Create JPA entities in infrastructure/persistence that map to domain models. Implement Spring Data repositories. Validate : Run @DataJpaTest to verify entity mapping and repository integration. 5. Implement Application Services Create @Transactional service classes that orchestrate domain operations and DTO mapping. Validate : Ensure transaction boundaries are correct and optimistic locking is applied where needed. 6. Define DTOs and Controllers Use Java records for API contracts with jakarta.validation annotations. Map REST endpoints with proper status codes. Validate : Test validation constraints and verify HTTP status codes (201 POST, 200 GET, 204 DELETE). 7. Validate and Deploy Run integration tests with Testcontainers. Verify migrations (Liquibase/Flyway) mirror the aggregate schema. Validate : Execute full test suite before deployment; confirm schema migration scripts are applied. See references/examples product feature.md for complete code aligned with each step. Examples Java Code Example: Product Feature JSON Input/Output Examples Create Request: Created Response (201): Paginated List Request: Best Practices Co locate domain, application, and presentation code per aggregate within feature packages. Use Java records for immutable DTOs; convert domain types at the service boundary. Apply transactions and optimistic locking for write operations. Normalize pagination defaults (page, size, sort) and document query parameters. Log CRUD lifecycle events (create, update, delete) at info level with structured audit trails. Surface health and metrics through Spring Boot Actuator; monitor throughput and error rates. Constraints and Warnings Never expose JPA entities directly in controllers to prevent lazy loading leaks and serialization issues. Never mix field injection with constructor injection; maintain immutability for testability. Never embed business logic in controllers or repository adapters; keep it in domain/application layers. Always validate input aggressively to prevent constraint violations and produce consistent error payloads. Always ensure migrations (Liquibase/Flyway) mirror aggregate evolution before deploying schema changes. Always run integration tests with Testcontainers before merging to prevent persistence regressions. References [HTTP methods, annotations, DTO patterns](references/crud reference.md) [Progressive examples from starter to advanced](references/examples product feature.md) [Spring Boot official documentation](references/spring official docs.md) [CRUD generator script](scripts/generate crud boilerplate.py) python scripts/generate crud boilerplate.py spec entity.json package com.example.product output ./generated

spring-boot-crud-patterns