[BE-pio] feat: CardService 구현

Related to #9

backend/src/main/java/com/team05/todolist/service/CardService.java

@@ -0,0 +1,51 @@
+package com.team05.todolist.service;
+
+import com.team05.todolist.controller.RequestCardDto;
+import com.team05.todolist.controller.ResponseCardDto;
+import com.team05.todolist.domain.Card;
+import com.team05.todolist.domain.Log;
+import com.team05.todolist.repository.CardRepository;
+import com.team05.todolist.repository.LogRepository;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.Optional;
+import org.springframework.stereotype.Service;
+
+@Service
+public class CardService {
+
+    private final CardRepository cardRepository;
+    private final LogRepository logRepository;
+
+    public CardService(CardRepository cardRepository, LogRepository logRepository) {
+        this.cardRepository = cardRepository;
+        this.logRepository = logRepository;
+    }
+
+    public List<Card> findCards() {
+        return cardRepository.findAll();
+    }
+
+    public List<Log> findLogs() {
+        return logRepository.findAll();
+    }
+
+    public ResponseCardDto findOne(int id) throws NoSuchElementException {
+        Optional<Card> card = cardRepository.findById(id);
+        return card.orElseThrow();
+    }
+
+    public void update(RequestCardDto updateCardDto) {
+        Card updateTargetCard = findOne(updateCardDto.getId());
+        updateTargetCard.changeSection(updateCardDto.getSection());
+        updateTargetCard.changeTitle(updateCardDto.getTitle());
+        updateTargetCard.changeContent(updateCardDto.getContent());
+        updateTargetCard.changeOrderIndex(updateCardDto.getOrderIndex());
+
+        cardRepository.save(updateTargetCard);
+    }
+
+    public void delete(RequestCardDto requestCardDto) {
+
+    }
+}