feat: 🎸 로그인된 사용자가 가입된 그룹 목록을 조회하는 기능 구현

✅ Closes: #226

src/main/java/com/postsquad/scoup/web/group/controller/GroupController.java

@@ -4,6 +4,7 @@
 import com.postsquad.scoup.web.error.controller.response.ErrorResponse;
 import com.postsquad.scoup.web.group.controller.request.GroupCreationRequest;
 import com.postsquad.scoup.web.group.controller.request.GroupModificationRequest;
+import com.postsquad.scoup.web.group.controller.response.GroupReadAllResponses;
 import com.postsquad.scoup.web.group.controller.request.GroupValidationRequest;
 import com.postsquad.scoup.web.group.controller.response.GroupReadOneResponse;
 import com.postsquad.scoup.web.group.controller.response.GroupValidationResponse;
@@ -71,4 +72,9 @@ public GroupValidationResponse validateGroupName(@Valid GroupValidationRequest g
     @ResponseStatus(HttpStatus.NO_CONTENT)
     public void leaveGroup(@PathVariable long groupId) {
     }
+
+    @GetMapping
+    public GroupReadAllResponses readAll(@LoggedInUser User user) {
+        return groupService.readAllByUser(user);
+    }
 }

src/main/java/com/postsquad/scoup/web/group/service/GroupService.java

@@ -3,21 +3,27 @@
 import com.postsquad.scoup.web.common.DefaultPostResponse;
 import com.postsquad.scoup.web.group.controller.request.GroupCreationRequest;
 import com.postsquad.scoup.web.group.controller.request.GroupModificationRequest;
+import com.postsquad.scoup.web.group.controller.response.GroupReadAllResponses;
 import com.postsquad.scoup.web.group.domain.Group;
 import com.postsquad.scoup.web.group.exception.GroupNameAlreadyExistException;
 import com.postsquad.scoup.web.group.exception.GroupNotFoundException;
 import com.postsquad.scoup.web.group.mapper.GroupMapper;
 import com.postsquad.scoup.web.group.repository.GroupRepository;
 import com.postsquad.scoup.web.signin.exception.UnauthorizedUserException;
+import com.postsquad.scoup.web.signin.exception.UserNotFoundException;
 import com.postsquad.scoup.web.user.domain.User;
+import com.postsquad.scoup.web.user.repository.UserRepository;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
+import java.util.stream.Collectors;
+
 @RequiredArgsConstructor
 @Service
 public class GroupService {
 
     private final GroupRepository groupRepository;
+    private final UserRepository userRepository;
 
     public DefaultPostResponse create(GroupCreationRequest groupCreationRequest, User user) {
 
@@ -42,4 +48,15 @@ public Long update(Long groupId, GroupModificationRequest groupModificationReque
         }
         return groupRepository.save(group.update(groupModificationRequest)).getId();
     }
+
+    public GroupReadAllResponses readAllByUser(User user) {
+        User loggedInUser = userRepository.findById(user.getId()).orElseThrow(() -> new UserNotFoundException(user.getId()));
+        return GroupReadAllResponses
+                .builder()
+                .groupReadAllResponse(
+                        loggedInUser.getJoinedGroups().stream()
+                                .map(GroupMapper.INSTANCE::map)
+                                .collect(Collectors.toList()))
+                .build();
+    }
 }