Feat: 그룹 내 전체 유저 조회

src/main/java/slvtwn/khu/toyouserver/application/GroupService.java

@@ -1,36 +1,54 @@
 package slvtwn.khu.toyouserver.application;
 
+import java.util.List;
+import java.util.stream.Collectors;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import slvtwn.khu.toyouserver.common.ErrorType;
 import slvtwn.khu.toyouserver.domain.Group;
+import slvtwn.khu.toyouserver.domain.MemberRepository;
 import slvtwn.khu.toyouserver.domain.User;
 import slvtwn.khu.toyouserver.dto.GroupResponse;
 import slvtwn.khu.toyouserver.exception.ToyouException;
 import slvtwn.khu.toyouserver.persistance.GroupRepository;
 import slvtwn.khu.toyouserver.persistance.UserRepository;
+import slvtwn.khu.toyouserver.presentation.GroupMemberResponse;
 
 @Service
 @Transactional(readOnly = true)
 public class GroupService {
 
-    private final GroupRepository groupRepository;
-    private final UserRepository userRepository;
+	private final GroupRepository groupRepository;
+	private final UserRepository userRepository;
+	private final MemberRepository memberRepository;
 
-    public GroupService(GroupRepository groupRepository, UserRepository userRepository) {
-        this.groupRepository = groupRepository;
-        this.userRepository = userRepository;
-    }
+	public GroupService(GroupRepository groupRepository, UserRepository userRepository,
+	                    MemberRepository memberRepository) {
+		this.groupRepository = groupRepository;
+		this.userRepository = userRepository;
+		this.memberRepository = memberRepository;
+	}
 
-    @Transactional
-    public GroupResponse registerUser(long groupId, long userId) {
-        Group group = groupRepository.findById(groupId)
-                .orElseThrow(() -> new ToyouException(ErrorType.GROUP_NOT_FOUND));
-        User user = userRepository.findById(userId)
-                .orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
+	@Transactional
+	public GroupResponse registerUser(long groupId, long userId) {
+		Group group = groupRepository.findById(groupId)
+				.orElseThrow(() -> new ToyouException(ErrorType.GROUP_NOT_FOUND));
+		User user = userRepository.findById(userId)
+				.orElseThrow(() -> new ToyouException(ErrorType.USER_NOT_FOUND));
 
-        // TODO : 그룹에 유저를 가입시킨다. 유저는 멤버로 등록된다.
+		// TODO : 그룹에 유저를 가입시킨다. 유저는 멤버로 등록된다.
 //		group.addMember(user);
-        return new GroupResponse(group.getId(), group.getName());
-    }
+		return new GroupResponse(group.getId(), group.getName());
+	}
+
+	@Transactional
+	public List<GroupMemberResponse> getRegisteredMembers(long groupId) {
+		return memberRepository.findByGroupId(groupId).stream()
+				.map(member -> new GroupMemberResponse(
+						member.getId(),
+						member.getUser().getId(),
+						member.getUser().getName(),
+						member.getUser().getProfilePicture()))
+				.collect(Collectors.toList());
+	}
 }

src/main/java/slvtwn/khu/toyouserver/domain/MemberRepository.java

@@ -0,0 +1,10 @@
+package slvtwn.khu.toyouserver.domain;
+
+import java.util.List;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface MemberRepository extends JpaRepository<Member, Long> {
+	List<Member> findByGroupId(Long groupId);
+}

src/main/java/slvtwn/khu/toyouserver/presentation/GroupController.java

@@ -1,6 +1,8 @@
 package slvtwn.khu.toyouserver.presentation;
 
+import java.util.List;
 import lombok.RequiredArgsConstructor;
+import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RestController;
@@ -11,10 +13,15 @@
 @RestController
 public class GroupController {
 
-    private final GroupService groupService;
+	private final GroupService groupService;
 
-    @PostMapping("/groups/{groupId}/members")
-    public GroupResponse registerMember(@PathVariable long groupId) {
-        return groupService.registerUser(groupId, 1L); // TODO: user -> argumentResolver 등록 필요
-    }
+	@PostMapping("/groups/{groupId}/members")
+	public GroupResponse registerMember(@PathVariable long groupId) {
+		return groupService.registerUser(groupId, 1L); // TODO: user -> argumentResolver 등록 필요
+	}
+
+	@GetMapping("/groups/{groupId}/members")
+	public List<GroupMemberResponse> getRegisteredMembers(@PathVariable long groupId) {
+		return groupService.getRegisteredMembers(groupId);
+	}
 }

src/main/java/slvtwn/khu/toyouserver/presentation/GroupMemberResponse.java

@@ -0,0 +1,4 @@
+package slvtwn.khu.toyouserver.presentation;
+
+public record GroupMemberResponse(Long id, Long userId, String name, String profilePicture) {
+}