<aside> 📌 우리는 JPA라는 개념을 배우고 유저 테이블에 JPA를 적용해 보았습니다. 몇 가지 문제를 통해 JPA를 연습해 봅시다! 🔥

</aside>

[Q1]

• FruitEntity

  @Entity(name = "fruit")
  public class FruitEntity {
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      private Long id;
  
      @Column(nullable = false)
      private String name;
  
      @Column(nullable = false)
      private LocalDate warehousingDate;
  
      @Column(nullable = false)
      private long price;
  
      @Column(nullable = false)
      private boolean isSold;
  
      protected FruitEntity() {}
  
      public FruitEntity(String name, LocalDate warehousingDate, long price) {
          this.name = name;
          this.warehousingDate = warehousingDate;
          this.price = price;
          this.isSold = false;
      }
      public void updateSoldState() {
          this.isSold = true;
      }
      ...
   }
  

• FruitRepository

  public interface FruitRepository extends JpaRepository<FruitEntity, Long> {
      List<FruitEntity> findByName(String name);
  }
  
  

• FruitService

  @Service
  public class FruitService {
      private final FruitRepository fruitRepository;
  
      public FruitService(FruitRepository fruitRepository) {
          this.fruitRepository = fruitRepository;
      }
  
      public void saveFruit(FruitCreateRequest request) {
          FruitEntity fruit = new FruitEntity(request.getName(), request.getWarehousingDate(), request.getPrice());
          fruitRepository.save(fruit);
      }
  
      public void updateFruit(FruitUpdateRequest request) {
          FruitEntity fruit = fruitRepository.findById(request.getId())
                  .orElseThrow(IllegalArgumentException::new);
          fruit.updateSoldState();
          fruitRepository.save(fruit);
      }
  
      public FruitAmountResponse calculateAmountFruit(String name) {
          List<FruitEntity> fruits = fruitRepository.findByName(name);
          long salesAmount = fruits.stream()
                  .filter(FruitEntity::isSold)
                  .mapToLong(FruitEntity::getPrice)
                  .sum();
  
          long notSalesAmount = fruits.stream()
                  .filter(fruit -> !fruit.isSold())
                  .mapToLong(FruitEntity::getPrice)
                  .sum();
          return new FruitAmountResponse(salesAmount, notSalesAmount);
      }
  }
  

[Q2]

• FruitController

      @GetMapping("/api/v1/fruit/count")
      public FruitCountResponse getFruitCount(@RequestParam String name) {
          return fruitService.getFruitCount(name);
      }
  

• FruitCountResponse

  public class FruitCountResponse {
      private long count;
  
      public FruitCountResponse(long count) {
          this.count = count;
      }
  
      public long getCount() {
          return count;
      }
  }
  

• FruitService

      public FruitCountResponse getFruitCount(String name) {
          return new FruitCountResponse(fruitRepository.countAllByName(name));
      }
  

• FruitRepository

  public interface FruitRepository extends JpaRepository<FruitEntity, Long> {
      List<FruitEntity> findByName(String name);
      long countAllByName(String name);
  }
  

• 결과

  

[Q3]