refactor: 优化其他 Service 实现和 Controller 代码

src/main/java/com/guo/learningprogresstracker/controller/StudySessionController.java

@@ -1,13 +1,10 @@
 package com.guo.learningprogresstracker.controller;
 
-import com.baomidou.mybatisplus.core.toolkit.Wrappers;
 import com.google.protobuf.ServiceException;
 import com.guo.learningprogresstracker.dto.request.EndedStudySessionRequest;
 import com.guo.learningprogresstracker.dto.response.StudySessionResponse;
 import com.guo.learningprogresstracker.entity.CommonResult;
-import com.guo.learningprogresstracker.entity.StudySessionsEntity;
 import com.guo.learningprogresstracker.exception.ErrorParameterException;
-import com.guo.learningprogresstracker.mapStruct.StudySessionConvert;
 import com.guo.learningprogresstracker.service.impl.StudySessionsServiceImpl;
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.NotEmpty;
@@ -15,8 +12,8 @@ import lombok.RequiredArgsConstructor;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
 
-import java.time.LocalDateTime;
 import java.util.ArrayList;
+import java.time.LocalDateTime;
 
 /**
  * 学习会话控制层
@@ -39,11 +36,9 @@ public class StudySessionController {
      */
     @GetMapping("/{sessionNum}")
     public CommonResult<StudySessionResponse> getStudySessionBySessionNum(@NotEmpty(message = "sessionNum不可为空") @PathVariable String sessionNum) throws ErrorParameterException {
-        StudySessionsEntity studySessionsEntity = studySessionsServiceImpl.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
-                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
-                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
-        StudySessionResponse studySessionResponse = StudySessionConvert.MAPPER.toStudySessionResponse(studySessionsEntity);
-        return CommonResult.success(studySessionResponse);
+        // 通过 service 层获取，包含归属校验
+        StudySessionResponse response = studySessionsServiceImpl.getStudySessionBySessionNum(sessionNum);
+        return CommonResult.success(response);
     }
 
     /**