입장코드로 그룹 참여 api

Author: eunhye-ahn

polling-app-server/src/main/java/com/example/polls/controller/GroupController.java

@@ -2,9 +2,9 @@
 
 import com.example.polls.model.User;
 import com.example.polls.payload.Request.CreateGroupRequest;
+import com.example.polls.payload.Request.JoinGroupRequest;
 import com.example.polls.payload.Response.GroupSummaryResponse;
 import com.example.polls.repository.UserRepository;
-import com.example.polls.security.CustomUserDetailsService;
 import com.example.polls.security.UserPrincipal;
 import com.example.polls.service.GroupService;
 import lombok.RequiredArgsConstructor;
@@ -29,14 +29,6 @@ public ResponseEntity<GroupSummaryResponse> createGroup(
             @RequestBody CreateGroupRequest request,
             @AuthenticationPrincipal UserPrincipal userPrincipal) {
 
-        System.out.println(">>> userPrincipal = " + userPrincipal);
-        System.out.println(">>> request.name = " + request.getName());
-        System.out.println(">>> request.memberIds = " + request.getMemberIds());
-
-        if (userPrincipal == null) {
-            throw new RuntimeException("userPrincipal이 null입니다.");
-        }
-
         User creator = userRepository.findById(userPrincipal.getId())
                 .orElseThrow(()-> new RuntimeException("사용자 없음"));
 
@@ -51,4 +43,10 @@ public ResponseEntity<List<GroupSummaryResponse>> getMyGroups(@AuthenticationPri
         return ResponseEntity.ok(groups);
     }
 
+    @PostMapping("/join")
+    public ResponseEntity<String> joinGroup(@RequestBody JoinGroupRequest request, @AuthenticationPrincipal UserPrincipal userPrincipal) {
+        groupService.joinCode(userPrincipal.getId(),request.getJoinCode());
+        return ResponseEntity.ok("그룹에 성공적으로 참여했습니다.");
+    }
+
 }

polling-app-server/src/main/java/com/example/polls/exception/AlreadyJoinedException.java

@@ -0,0 +1,7 @@
+package com.example.polls.exception;
+
+public class AlreadyJoinedException extends RuntimeException {
+    public AlreadyJoinedException(String message) {
+        super(message);
+    }
+}

polling-app-server/src/main/java/com/example/polls/exception/GlobalExceptionHandler.java

@@ -0,0 +1,45 @@
+package com.example.polls.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+import java.util.Map;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    // 400 Bad Request
+    @ExceptionHandler(BadRequestException.class)
+    public ResponseEntity<?> handleBadRequest(BadRequestException ex) {
+        return buildErrorResponse(HttpStatus.BAD_REQUEST, ex.getMessage());
+    }
+
+    // 404 Not Found
+    @ExceptionHandler(ResourceNotFoundException.class)
+    public ResponseEntity<?> handleNotFound(ResourceNotFoundException ex) {
+        return buildErrorResponse(HttpStatus.NOT_FOUND, ex.getMessage());
+    }
+
+    // 409 Conflict
+    @ExceptionHandler(AlreadyJoinedException.class)
+    public ResponseEntity<?> handleConflict(AlreadyJoinedException ex) {
+        return buildErrorResponse(HttpStatus.CONFLICT, ex.getMessage());
+    }
+
+    // 500 Internal Server Error (예외 누락 시 fallback)
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<?> handleException(Exception ex) {
+        return buildErrorResponse(HttpStatus.INTERNAL_SERVER_ERROR, "서버 오류가 발생했습니다.");
+    }
+
+    // 공통 응답 포맷 생성 메서드
+    private ResponseEntity<?> buildErrorResponse(HttpStatus status, String message) {
+        return ResponseEntity.status(status).body(Map.of(
+                "status", status.value(),
+                "error", status.getReasonPhrase(),
+                "message", message
+        ));
+    }
+}

polling-app-server/src/main/java/com/example/polls/payload/Request/JoinGroupRequest.java

@@ -0,0 +1,13 @@
+package com.example.polls.payload.Request;
+
+public class JoinGroupRequest {
+    private String joinCode;
+
+    public String getJoinCode() {
+        return joinCode;
+    }
+
+    public void setJoinCode(String joinCode) {
+        this.joinCode = joinCode;
+    }
+}

polling-app-server/src/main/java/com/example/polls/repository/GroupMemberRepository.java

@@ -11,4 +11,6 @@
 public interface GroupMemberRepository extends JpaRepository<GroupMember, Long> {
     @Query("SELECT gm.group FROM GroupMember gm WHERE gm.user.id = :userId")
     List<Group> findGroupsByUserId(@Param("userId") Long userId);
+
+    boolean existsByUserIdAndGroupId(Long userId, Long groupId);
 }

polling-app-server/src/main/java/com/example/polls/service/GroupService.java

@@ -1,5 +1,8 @@
 package com.example.polls.service;
 
+import com.example.polls.exception.AlreadyJoinedException;
+import com.example.polls.exception.BadRequestException;
+import com.example.polls.exception.ResourceNotFoundException;
 import com.example.polls.model.Group;
 import com.example.polls.model.GroupMember;
 import com.example.polls.model.GroupRole;
@@ -13,7 +16,6 @@
 import org.springframework.stereotype.Service;
 
 import javax.transaction.Transactional;
-import java.util.Collection;
 import java.util.List;
 import java.util.UUID;
 import java.util.stream.Collectors;
@@ -83,4 +85,26 @@ public List<GroupSummaryResponse> getGroupsForUser(Long userId) {
                 .map(GroupSummaryResponse::new)
                 .collect(Collectors.toList());
     }
+
+    //조인 코드로 그룹 참여
+    public void joinCode(Long userId, String joinCode) {
+        Group group = groupRepository.findByJoinCode(joinCode)
+                .orElseThrow(()-> new BadRequestException("유효하지 않은 입장코드입니다."));
+
+        //중복 참여 체크
+        boolean alreadyJoined = groupMemberRepository.existsByUserIdAndGroupId(userId, group.getId());
+        if(alreadyJoined){
+            throw new AlreadyJoinedException("이미 참여한 그룹입니다.");
+        }
+
+        User user = userRepository.findById(userId)
+                .orElseThrow(()-> new ResourceNotFoundException("User", "id", userId));
+
+        GroupMember newMember = new GroupMember();
+        newMember.setGroup(group);
+        newMember.setUser(user);
+        newMember.setRole(GroupRole.MEMBER);
+        groupMemberRepository.save(newMember);
+
+    }
 }