✨ Feat/#307 강의 id로 클래스 제목 조회 api 구현

backend/src/main/java/org/example/backend/domain/lecture/controller/LectureController.java

@@ -101,4 +101,10 @@ public ApiResponse<StudentTodayLectureResponseDTO> getStudentLectures(@RequestPa
         return ApiResponse.onSuccess(result);
     }
 
-}
+    // lecture id로 class id 조회
+    @GetMapping("/classes/{lectureId}")
+    public ApiResponse<ClassNameResponseDTO> getClassId(@PathVariable("lectureId") UUID lectureId) {
+        ClassNameResponseDTO result = lectureService.getClassId(lectureId);
+        return ApiResponse.onSuccess(result);
+    }
+}

backend/src/main/java/org/example/backend/domain/lecture/dto/response/ClassNameResponseDTO.java

@@ -0,0 +1,15 @@
+package org.example.backend.domain.lecture.dto.response;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+
+@Getter
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class ClassNameResponseDTO {
+    private String className;
+}

backend/src/main/java/org/example/backend/domain/lecture/service/LectureService.java

@@ -1,6 +1,7 @@
 package org.example.backend.domain.lecture.service;
 
 import org.example.backend.domain.lecture.dto.request.LectureRequestDTO;
+import org.example.backend.domain.lecture.dto.response.ClassNameResponseDTO;
 import org.example.backend.domain.lecture.dto.response.LectureRecordingResponseDTO;
 import org.example.backend.domain.lecture.dto.response.LectureResponseDTO;
 import org.example.backend.domain.lecture.dto.response.TodayLectureResponseDTO;
@@ -27,4 +28,6 @@ public interface LectureService {
     List<UUID> mapNotes(UUID lectureId, List<UUID> lectureNoteIds);
 
     List<TodayLectureResponseDTO> getClassListByProfessor(LocalDate date);
+
+    ClassNameResponseDTO getClassId(UUID lectureId);
 }

backend/src/main/java/org/example/backend/domain/lecture/service/LectureServiceImpl.java

@@ -6,6 +6,7 @@
 import org.example.backend.domain.classroom.repository.ClassroomRepository;
 import org.example.backend.domain.lecture.converter.LectureConverter;
 import org.example.backend.domain.lecture.dto.request.LectureRequestDTO;
+import org.example.backend.domain.lecture.dto.response.ClassNameResponseDTO;
 import org.example.backend.domain.lecture.dto.response.LectureRecordingResponseDTO;
 import org.example.backend.domain.lecture.dto.response.LectureResponseDTO;
 import org.example.backend.domain.lecture.dto.response.TodayLectureResponseDTO;
@@ -303,5 +304,17 @@ public void updateLectureSessions(UUID classId) {
         lectureRepository.saveAll(lectures);
     }
 
+    // 강의 id 기반 클래스 id 조회
+    @Override
+    public ClassNameResponseDTO getClassId(UUID lectureId) {
+        // 1. 강의 조회
+        Lecture lecture = lectureRepository.findById(lectureId)
+                .orElseThrow(() -> new LectureException(LectureErrorCode.LECTURE_NOT_FOUND));
+        // 2. 클래스 조회
+        Classroom classroom = lecture.getClassroom();
 
+        return ClassNameResponseDTO.builder()
+                .className(classroom.getClassName())
+                .build();
+    }
 }