spring-boot

name	spring-boot
description	Spring Boot 3+ expert for building enterprise Java applications. Covers REST APIs, security, data access, and microservices patterns.
license	MIT
compatibility	opencode
metadata	{"audience":"developers","category":"backend"}

Spring Boot Expert

What I Do

• Build REST APIs with Spring Web and Spring Data
• Configure Spring Security for authentication and authorization
• Implement reactive programming with WebFlux
• Set up Spring Data JPA with proper entity design
• Configure microservices with Spring Cloud

When to Use Me

• Creating Spring Boot applications
• Designing RESTful APIs
• Implementing security with Spring Security
• Setting up database access with Spring Data
• Building microservices architectures

Key Principles

1. Constructor Injection: Always prefer constructor over field injection
2. DTO Pattern: Never expose entities directly in API responses
3. Exception Handling: Use @ControllerAdvice for centralized error handling
4. Validation: Use Bean Validation (@Valid) at API boundaries
5. Profiles: Use application profiles for environment-specific config

Common Patterns

REST Controller

@RestController
@RequestMapping("/api/users")
@RequiredArgsConstructor
public class UserController {
    private final UserService userService;

    @GetMapping("/{id}")
    public ResponseEntity<UserDto> getUser(@PathVariable Long id) {
        return userService.findById(id)
            .map(ResponseEntity::ok)
            .orElse(ResponseEntity.notFound().build());
    }

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public UserDto createUser(@Valid @RequestBody CreateUserRequest request) {
        return userService.create(request);
    }
}

Global Exception Handler

@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(EntityNotFoundException.class)
    public ResponseEntity<ErrorResponse> handleNotFound(EntityNotFoundException ex) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND)
            .body(new ErrorResponse(ex.getMessage()));
    }
}

Validation

./mvnw test
./mvnw spring-boot:run