Know-How
Spring Boot 3 tutorial
Spring Boot 3 + Java 21 = moderní Java backend. Auto-konfigurace, dependency injection, obrovský ekosystém.
REST API
@RestController
@RequestMapping("/api/users")
public class UserController {
private final UserRepository repo;
public UserController(UserRepository repo) {
this.repo = repo;
}
@GetMapping
public List findAll() {
return repo.findAll();
}
@PostMapping
@ResponseStatus(HttpStatus.CREATED)
public User create(@Valid @RequestBody User user) {
return repo.save(user);
}
@GetMapping("/{id}")
public User findById(@PathVariable Long id) {
return repo.findById(id)
.orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND));
}
}
JPA Entity
@Entity
public class User {
@Id @GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@NotBlank private String name;
@Email private String email;
// getters, setters
}
public interface UserRepository extends JpaRepository {
List findByNameContaining(String name);
}
Klíčový takeaway
Spring Boot 3 + Java 21 + virtual threads = moderní Java. JPA pro databázi, Spring Security pro auth.