Spring BootSpring Boot

@SpringBootApplication  // @Configuration + @EnableAutoConfiguration + @ComponentScan
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@RestController
@RequestMapping("/api/items")
public class ItemController {
    private final ItemService itemService;

    public ItemController(ItemService itemService) {
        this.itemService = itemService;
    }

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

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public ItemDto createItem(@Valid @RequestBody ItemDto dto) {
        return itemService.create(dto);
    }
}

@Entity
@Table(name = "items")
public class Item {
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String name;

    private BigDecimal price;
}

public interface ItemRepository extends JpaRepository<Item, Long> {
    List<Item> findByNameContaining(String keyword);

    @Query("SELECT i FROM Item i WHERE i.price < :maxPrice")
    List<Item> findCheapItems(@Param("maxPrice") BigDecimal maxPrice);
}

spring:
  datasource:
    url: jdbc:postgresql://localhost:5432/mydb
    username: user
    password: pass
  jpa:
    hibernate:
      ddl-auto: validate
    show-sql: false
  cache:
    type: redis

server:
  port: 8080