feat: 新增碎片更新和会话查询的Service实现

- StudyReportFragmentsService 接口新增 updateFragments 和 getFragmentsBySession 方法
- ServiceImpl 实现碎片更新（校验存在性后更新）和按会话编号查询碎片列表

src/main/java/com/guo/learningprogresstracker/service/StudyReportFragmentsService.java

@@ -1,10 +1,13 @@
 package com.guo.learningprogresstracker.service;
 
 import com.guo.learningprogresstracker.dto.request.CreateFragmentsRequest;
+import com.guo.learningprogresstracker.dto.request.UpdateFragmentsRequest;
 import com.guo.learningprogresstracker.entity.StudyReportFragmentsEntity;
 import com.baomidou.mybatisplus.extension.service.IService;
 import com.guo.learningprogresstracker.exception.NotFindEntitiesException;
 
+import java.util.List;
+
 /**
 * @author guo
 * @description 针对表【study_report_fragments(记录学习过程中的学习内容报告残片)】的数据库操作Service
@@ -13,4 +16,8 @@ import com.guo.learningprogresstracker.exception.NotFindEntitiesException;
 public interface StudyReportFragmentsService extends IService<StudyReportFragmentsEntity> {
 
     void createFragments(CreateFragmentsRequest request) throws NotFindEntitiesException;
+
+    void updateFragments(Integer id, UpdateFragmentsRequest request) throws NotFindEntitiesException;
+
+    List<StudyReportFragmentsEntity> getFragmentsBySession(String sessionNum);
 }

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

@@ -3,6 +3,7 @@ package com.guo.learningprogresstracker.service.impl;
 import com.baomidou.mybatisplus.core.toolkit.Wrappers;
 import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
 import com.guo.learningprogresstracker.dto.request.CreateFragmentsRequest;
+import com.guo.learningprogresstracker.dto.request.UpdateFragmentsRequest;
 import com.guo.learningprogresstracker.entity.StudyReportFragmentsEntity;
 import com.guo.learningprogresstracker.entity.StudySessionsEntity;
 import com.guo.learningprogresstracker.exception.NotFindEntitiesException;
@@ -13,6 +14,8 @@ import com.guo.learningprogresstracker.mapper.StudyReportFragmentsMapper;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
+import java.util.List;
+
 /**
  * 针对表【study_report_fragments(记录学习过程中的学习内容报告残片)】的数据库操作Service实现
  */
@@ -34,4 +37,23 @@ public class StudyReportFragmentsServiceImpl extends ServiceImpl<StudyReportFrag
         }
         this.save(entity);
     }
+
+    @Override
+    public void updateFragments(Integer id, UpdateFragmentsRequest request) throws NotFindEntitiesException {
+        StudyReportFragmentsEntity existing = this.getById(id);
+        if (existing == null) {
+            throw new NotFindEntitiesException(String.format("未能找到学习残片id[%d]", id));
+        }
+        StudyReportFragmentsEntity entity = FragmentsConvert.MAPPER.toFragmentsEntity(request);
+        entity.setId(id);
+        this.updateById(entity);
+    }
+
+    @Override
+    public List<StudyReportFragmentsEntity> getFragmentsBySession(String sessionNum) {
+        return this.list(
+                Wrappers.lambdaQuery(StudyReportFragmentsEntity.class)
+                        .eq(StudyReportFragmentsEntity::getSessionNum, sessionNum)
+                        .orderByAsc(StudyReportFragmentsEntity::getCreatedTime));
+    }
 }