spring-boot-engineer

name spring-boot-engineer description Generates Spring Boot 3.x configurations, creates REST controllers, implements Spring Security 6 authentication flows, sets up Spring Data JPA repositories, and configures reactive WebFlux endpoints. Use when building Spring Boot 3.x applications, microservices, or reactive Java applications; invoke for Spring Data JPA, Spring Security 6, WebFlux, Spring Cloud integration, Java REST API design, or Microservices Java architecture. license MIT metadata {"author":"https://github.com/Jeffallan","version":"1.1.0","domain":"backend","triggers":"Spring Boot, Spring Framework, Spring Cloud, Spring Security, Spring Data JPA, Spring WebFlux, Microservices Java, Java REST API, Reactive Java","role":"specialist","scope":"implementation","output-format":"code","related-skills":"java-architect, database-optimizer, microservices-architect, devops-engineer"} Spring Boot Engineer Core Workflow Analyze requirements — Identify service boundaries, APIs, data models, security needs Design architecture — Plan microservices, data access, cloud integration, security; confirm design before coding Implement — Create services with constructor injection and layered architecture (see Quick Start below) Secure — Add Spring Security, OAuth2, method security, CORS configuration; verify security rules compile and pass tests. If compilation or tests fail: review error output, fix the failing rule or configuration, and re-run before proceeding Test — Write unit, integration, and slice tests; run ./mvnw test (or ./gradlew test ) and confirm all pass before proceeding. If tests fail: review the stack trace, isolate the failing assertion or component, fix the issue, and re-run the full suite Deploy — Configure health checks and observability via Actuator; validate /actuator/health returns UP . If health is DOWN : check the components detail in the response, resolve the failing component (e.g., datasource, broker), and re-validate Reference Guide Load detailed guidance based on context: Topic Reference Load When Web Layer references/web.md Controllers, REST APIs, validation, exception handling Data Access references/data.md Spring Data JPA, repositories, transactions, projections Security references/security.md Spring Security 6, OAuth2, JWT, method security Cloud Native references/cloud.md Spring Cloud, Config, Discovery, Gateway, resilience Testing references/testing.md @SpringBootTest, MockMvc, Testcontainers, test slices Quick Start — Minimal Working Structure A standard Spring Boot feature consists of these layers. Use these as copy-paste starting points. Entity @Entity @Table(name = "products") public class Product { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @NotBlank private String name; @DecimalMin("0.0") private BigDecimal price; // getters / setters or use @Data (Lombok) } Repository public interface ProductRepository extends JpaRepository <Product, Long> { List<Product> findByNameContainingIgnoreCase (String name) ; } Service (constructor injection) @Service public class ProductService { private final ProductRepository repo; public ProductService (ProductRepository repo) { // constructor injection — no @Autowired this .repo = repo; } @Transactional(readOnly = true) public List<Product> search (String name) { return repo.findByNameContainingIgnoreCase(name); } @Transactional public Product create (ProductRequest request) { var product = new Product (); product.setName(request.name()); product.setPrice(request.price()); return repo.save(product); } } REST Controller @RestController @RequestMapping("/api/v1/products") @Validated public class ProductController { private final ProductService service; public ProductController (ProductService service) { this .service = service; } @GetMapping public List<Product> search ( @RequestParam(defaultValue = "") String name) { return service.search(name); } @PostMapping @ResponseStatus(HttpStatus.CREATED) public Product create ( @Valid @RequestBody ProductRequest request) { return service.create(request); } } DTO (record) public record ProductRequest ( @NotBlank String name, @DecimalMin("0.0") BigDecimal price ) {} Global Exception Handler @RestControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(MethodArgumentNotValidException.class) @ResponseStatus(HttpStatus.BAD_REQUEST) public Map<String, String> handleValidation (MethodArgumentNotValidException ex) { return ex.getBindingResult().getFieldErrors().stream() .collect(Collectors.toMap(FieldError::getField, FieldError::getDefaultMessage)); } @ExceptionHandler(EntityNotFoundException.class) @ResponseStatus(HttpStatus.NOT_FOUND) public Map<String, String> handleNotFound (EntityNotFoundException ex) { return Map.of( "error" , ex.getMessage()); } } Test Slice @WebMvcTest(ProductController.class) class ProductControllerTest { @Autowired MockMvc mockMvc; @MockBean ProductService service; @Test void createProduct_validRequest_returns201 () throws Exception { var product = new Product (); product.setName( "Widget" ); product.setPrice(BigDecimal.TEN); when (service.create(any())).thenReturn(product); mockMvc.perform(post( "/api/v1/products" ) .contentType(MediaType.APPLICATION_JSON) .content( """{"name":"Widget","price":10.0}""" )) .andExpect(status().isCreated()) .andExpect(jsonPath( "$.name" ).value( "Widget" )); } } Constraints MUST DO Rule Correct Pattern Constructor injection public MyService(Dep dep) { this.dep = dep; } Validate API input @Valid @RequestBody MyRequest req on every mutating endpoint Type-safe config @ConfigurationProperties(prefix = "app") bound to a record/class Appropriate stereotype @Service for business logic, @Repository for data, @RestController for HTTP Transaction scope @Transactional on multi-step writes; @Transactional(readOnly = true) on reads Hide internals Catch domain exceptions in @RestControllerAdvice ; return problem details, not stack traces Externalize secrets Use environment variables or Spring Cloud Config — never application.properties MUST NOT DO Use field injection ( @Autowired on fields) Skip input validation on API endpoints Use @Component when @Service / @Repository / @Controller applies Mix blocking and reactive code (e.g., calling .block() inside a WebFlux chain) Store secrets or credentials in application.properties / application.yml Hardcode URLs, credentials, or environment-specific values Use deprecated Spring Boot 2.x patterns (e.g., WebSecurityConfigurerAdapter ) Documentation