[xingyu.guo] feat: 1. 替换所有响应值中的id为num,不将非业务字段展示给外部 2. 调整[实际使用时间]等字段类型为double,方便计算\保存与读取 3. 【获取所有任务列表】api，完善功能，并增加分页功能 4.将int类型修改为使用Integer，更加安全

src/main/java/com/guo/learningprogresstracker/service/impl/StudySessionsServiceImpl.java

@@ -14,6 +14,7 @@ import com.guo.learningprogresstracker.service.StudySessionsService;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
+import java.time.LocalDateTime;
 import java.util.Optional;
 
 /**
@@ -41,6 +42,7 @@ public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, S
             // 返回一个新的会话
             StudySessionsEntity studySessionsEntity = StudySessionsEntity.initNewSession();
             studySessionsEntity.setTaskNum(taskNum);
+            studySessionsEntity.setLastStartTime(LocalDateTime.now());
             this.save(studySessionsEntity);
             return StudySessionConvert.MAPPER.toStudySessionResponce(studySessionsEntity);
         }else {
@@ -52,9 +54,10 @@ public class StudySessionsServiceImpl extends ServiceImpl<StudySessionsMapper, S
         }
     }
 
-    public void pauseStudySession(String sessionId) throws ErrorParameterException {
-        StudySessionsEntity studySessionsEntity = this.getOptById(sessionId)
-                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionId + "]不存在"));
+    public void pauseStudySession(String sessionNum) throws ErrorParameterException {
+        StudySessionsEntity studySessionsEntity = this.getOneOpt(Wrappers.lambdaQuery(StudySessionsEntity.class)
+                        .eq(StudySessionsEntity::getSessionNum, sessionNum))
+                .orElseThrow(() -> new ErrorParameterException("会话[" + sessionNum + "]不存在"));
         studySessionsEntity.pausedStudySession();
         this.updateById(studySessionsEntity);
     }