Merge remote-tracking branch 'origin/master'

# Conflicts:
#	reading-platform-frontend/src/views/admin/collections/CollectionEditView.vue

reading-platform-frontend/src/api/collections.ts

@@ -202,9 +202,21 @@ export function getCollectionStatusInfo(status: string) {
   return COLLECTION_STATUS_MAP[status] || { label: status, color: 'default' };
 }
 
-// 解析适用年级
+// 解析适用年级（统一处理列表展示与创建时的格式）
-export function parseGradeLevels(gradeLevels: string | string[]): string[] {
+export function parseGradeLevels(gradeLevels: string | string[] | undefined): string[] {
-  if (Array.isArray(gradeLevels)) return gradeLevels;
+  if (!gradeLevels) return [];
+  if (Array.isArray(gradeLevels)) {
+    if (gradeLevels.length === 0) return [];
+    // 兼容后端错误格式：["[\"小班\"", " \"中班\""] -> 拼接后解析
+    if (gradeLevels[0]?.toString().startsWith('[')) {
+      try {
+        return JSON.parse(gradeLevels.join(''));
+      } catch {
+        return [];
+      }
+    }
+    return gradeLevels;
+  }
   try {
     return JSON.parse(gradeLevels || '[]');
   } catch {

reading-platform-frontend/src/views/admin/collections/CollectionDetailView.vue

@@ -31,10 +31,14 @@
               </a-popconfirm>
             </template>
 
-            <!-- 已下架状态：显示重新发布按钮 -->
+            <!-- 已下架状态：显示编辑、删除、重新发布按钮 -->
             <template v-else-if="collection?.status === 'ARCHIVED'">
+              <a-button type="primary" @click="editCollection">编辑</a-button>
               <a-popconfirm title="确定要重新发布此套餐吗？" @confirm="handleRepublish">
-                <a-button type="primary">重新发布</a-button>
+                <a-button>重新发布</a-button>
+              </a-popconfirm>
+              <a-popconfirm title="确定要删除此套餐吗？" @confirm="handleDelete">
+                <a-button danger>删除</a-button>
               </a-popconfirm>
             </template>
 
@@ -284,10 +288,12 @@ const handleAddPackage = async () => {
 
   addingPackage.value = true;
   try {
-    // 获取当前课程包列表
+    // 获取当前课程包列表（去重）
-    const currentPackageIds = collection.value?.packages?.map(p => p.id) || [];
+    const currentPackageIds = [...new Set(collection.value?.packages?.map(p => p.id) || [])];
-    // 添加新的课程包ID
+    // 添加新的课程包ID（避免重复）
-    const newPackageIds = [...currentPackageIds, selectedPackageId.value];
+    const newPackageIds = currentPackageIds.includes(selectedPackageId.value)
+      ? currentPackageIds
+      : [...currentPackageIds, selectedPackageId.value];
 
     await collectionsApi.setCollectionPackages(route.params.id, newPackageIds);
     message.success('添加成功');
@@ -304,8 +310,8 @@ const handleAddPackage = async () => {
 // 移除课程包
 const handleRemovePackage = async (packageId: number) => {
   try {
-    // 获取当前课程包列表，移除指定的课程包
+    // 获取当前课程包列表（去重），移除指定的课程包
-    const currentPackageIds = collection.value?.packages?.map(p => p.id) || [];
+    const currentPackageIds = [...new Set(collection.value?.packages?.map(p => p.id) || [])];
     const newPackageIds = currentPackageIds.filter(id => id !== packageId);
 
     await collectionsApi.setCollectionPackages(route.params.id, newPackageIds);

reading-platform-frontend/src/views/admin/collections/CollectionListView.vue

@@ -6,38 +6,25 @@
       </template>
       <template #extra>
         <a-button type="primary" @click="handleCreate">
-          <template #icon><PlusOutlined /></template>
+          <template #icon>
+            <PlusOutlined />
+          </template>
           新建套餐
         </a-button>
       </template>
 
       <!-- 筛选 -->
       <div class="filter-section">
-        <a-select
+        <a-select v-model:value="filters.status" placeholder="状态筛选" style="width: 150px" allowClear @change="fetchData">
-          v-model:value="filters.status"
-          placeholder="状态筛选"
-          style="width: 150px"
-          allowClear
-          @change="fetchData"
-        >
           <a-select-option value="DRAFT">草稿</a-select-option>
-          <a-select-option value="PENDING">待审核</a-select-option>
-          <a-select-option value="APPROVED">已通过</a-select-option>
           <a-select-option value="PUBLISHED">已发布</a-select-option>
           <a-select-option value="ARCHIVED">已下架</a-select-option>
-          <a-select-option value="REJECTED">已驳回</a-select-option>
         </a-select>
       </div>
 
       <!-- 表格 -->
-      <a-table
+      <a-table :columns="columns" :data-source="dataSource" :loading="loading" :pagination="pagination" row-key="id"
-        :columns="columns"
+        @change="handleTableChange">
-        :data-source="dataSource"
-        :loading="loading"
-        :pagination="pagination"
-        row-key="id"
-        @change="handleTableChange"
-      >
         <template #bodyCell="{ column, record }">
           <template v-if="column.key === 'price'">
             {{ formatPrice(record.price) }}
@@ -57,6 +44,14 @@
               <template v-if="record.status === 'DRAFT'">
                 <a-button type="link" size="small" @click="handleView(record)">查看</a-button>
                 <a-button type="link" size="small" @click="handleEdit(record)">编辑</a-button>
+                <a-tooltip v-if="(record.packageCount || 0) === 0" title="请先添加至少一个课程包">
+                  <span>
+                    <a-button type="primary" size="small" disabled>发布</a-button>
+                  </span>
+                </a-tooltip>
+                <a-popconfirm v-else title="确定要发布此套餐吗？发布后学校端将可以查看。" @confirm="handlePublish(record)">
+                  <a-button type="primary" size="small">发布</a-button>
+                </a-popconfirm>
                 <a-popconfirm title="确定要删除吗？" @confirm="handleDelete(record)">
                   <a-button type="link" size="small" danger>删除</a-button>
                 </a-popconfirm>
@@ -72,6 +67,14 @@
               <template v-else-if="record.status === 'REJECTED'">
                 <a-button type="link" size="small" @click="handleView(record)">查看</a-button>
                 <a-button type="link" size="small" @click="handleEdit(record)">修改</a-button>
+                <a-tooltip v-if="(record.packageCount || 0) === 0" title="请先添加至少一个课程包">
+                  <span>
+                    <a-button type="primary" size="small" disabled>发布</a-button>
+                  </span>
+                </a-tooltip>
+                <a-popconfirm v-else title="确定要发布此套餐吗？发布后学校端将可以查看。" @confirm="handlePublish(record)">
+                  <a-button type="primary" size="small">发布</a-button>
+                </a-popconfirm>
               </template>
 
               <!-- 已通过状态 -->
@@ -91,9 +94,13 @@
               <!-- 已下架状态 -->
               <template v-else-if="record.status === 'ARCHIVED'">
                 <a-button type="link" size="small" @click="handleView(record)">查看</a-button>
+                <a-button type="link" size="small" @click="handleEdit(record)">编辑</a-button>
                 <a-popconfirm title="确定要重新发布吗？" @confirm="handleRepublish(record)">
                   <a-button type="primary" size="small">重新发布</a-button>
                 </a-popconfirm>
+                <a-popconfirm title="确定要删除吗？" @confirm="handleDelete(record)">
+                  <a-button type="link" size="small" danger>删除</a-button>
+                </a-popconfirm>
               </template>
             </a-space>
           </template>

reading-platform-frontend/src/views/admin/courses/CourseDetailView.vue

@@ -14,7 +14,7 @@
         </div>
       </div>
       <div class="header-actions">
-        <a-button @click="editCourse">
+        <a-button v-if="course.status !== 'PUBLISHED'" @click="editCourse">
           <EditOutlined /> 编辑
         </a-button>
         <a-button @click="viewStats">

reading-platform-frontend/src/views/admin/courses/CourseEditView.vue

@@ -218,6 +218,13 @@ const fetchCourseDetail = async () => {
     const res = await getCourse(courseId.value) as any;
     const course = res.data || res;
 
+    // 已发布的课程包不允许编辑
+    if (course?.status === 'PUBLISHED') {
+      message.warning('已发布的课程包不允许编辑，请使用「迭代版本」创建新版本');
+      router.push(`/admin/packages/${courseId.value}`);
+      return;
+    }
+
     // 基本信息
     formData.basic.name = course.name;
     formData.basic.themeId = course.themeId;

reading-platform-frontend/src/views/admin/packages/PackageEditView.vue

@@ -39,11 +39,12 @@
         </a-form-item>
 
         <a-form-item label="适用年级" name="gradeLevels">
-          <a-select v-model:value="form.gradeLevels" mode="multiple" placeholder="请选择适用年级" style="width: 300px">
+          <a-checkbox-group v-model:value="form.gradeLevels" disabled>
-            <a-select-option value="小班">小班</a-select-option>
+            <a-checkbox value="小班">小班</a-checkbox>
-            <a-select-option value="中班">中班</a-select-option>
+            <a-checkbox value="中班">中班</a-checkbox>
-            <a-select-option value="大班">大班</a-select-option>
+            <a-checkbox value="大班">大班</a-checkbox>
-          </a-select>
+          </a-checkbox-group>
+          <div v-if="form.gradeLevels.length === 0" class="grade-hint">根据已选课程包自动填充</div>
         </a-form-item>
 
         <a-divider>课程包配置</a-divider>
@@ -62,11 +63,8 @@
                   <a-input-number v-model:value="record.sortOrder" :min="0" size="small" />
                 </template>
                 <template v-else-if="column.key === 'gradeLevel'">
-                  <a-select v-model:value="record.gradeLevel" size="small" style="width: 100px">
+                  <a-tag v-for="g in (record.gradeLevels || [])" :key="g">{{ g }}</a-tag>
-                    <a-select-option value="小班">小班</a-select-option>
+                  <span v-if="!record.gradeLevels?.length">-</span>
-                    <a-select-option value="中班">中班</a-select-option>
-                    <a-select-option value="大班">大班</a-select-option>
-                  </a-select>
                 </template>
                 <template v-else-if="column.key === 'action'">
                   <a-button type="link" size="small" danger @click="removePackage(index)">移除</a-button>
@@ -115,7 +113,7 @@
 </template>
 
 <script setup lang="ts">
-import { ref, reactive, computed, onMounted } from 'vue';
+import { ref, reactive, computed, watch, onMounted } from 'vue';
 import { useRouter, useRoute } from 'vue-router';
 import { message } from 'ant-design-vue';
 import type { FormInstance } from 'ant-design-vue';
@@ -145,18 +143,23 @@ const form = reactive({
   gradeLevels: [] as string[],
 });
 
-const selectedPackages = ref<{ packageId: number | string; gradeLevel: string; sortOrder: number; packageName: string }[]>([]);
+const selectedPackages = ref<{ packageId: number | string; gradeLevels: string[]; sortOrder: number; packageName: string }[]>([]);
 
-// 表单校验规则
+// 表单校验规则（适用年级由已选课程包自动填充）
 const formRules = {
   name: [{ required: true, message: '请输入套餐名称' }],
   price: [{ required: true, message: '请输入价格' }],
-  gradeLevels: [{ required: true, message: '请选择适用年级' }],
+  gradeLevels: [{
+    validator: () => {
+      if (selectedPackages.value.length === 0) return Promise.reject('请先添加至少一个课程包');
+      return Promise.resolve();
+    },
+  }],
 };
 
 const packageColumns = [
   { title: '课程包', dataIndex: 'packageName', key: 'packageName' },
-  { title: '年级', dataIndex: 'gradeLevel', key: 'gradeLevel', width: 120 },
+  { title: '年级', dataIndex: 'gradeLevels', key: 'gradeLevel', width: 120 },
   { title: '排序', dataIndex: 'sortOrder', key: 'sortOrder', width: 80 },
   { title: '操作', key: 'action', width: 80 },
 ];
@@ -174,7 +177,8 @@ const rowSelection = computed(() => ({
   },
 }));
 
-const parseGradeTags = (tags: string) => {
+const parseGradeTags = (tags: string | string[]) => {
+  if (Array.isArray(tags)) return tags;
   try {
     return JSON.parse(tags || '[]');
   } catch {
@@ -182,6 +186,15 @@ const parseGradeTags = (tags: string) => {
   }
 };
 
+// 从已选课程包同步适用年级到表单（年级列只读，从课程包数据读取）
+const syncGradeLevelsFromPackages = () => {
+  const grades = [...new Set(selectedPackages.value.flatMap((p) => p.gradeLevels || []).filter(Boolean))];
+  form.gradeLevels = grades;
+};
+
+// 监听已选课程包变化（添加、移除、修改年级），自动同步适用年级
+watch(() => selectedPackages.value, syncGradeLevelsFromPackages, { deep: true });
+
 const fetchPackageDetail = async () => {
   if (!isEdit.value) return;
 
@@ -192,13 +205,13 @@ const fetchPackageDetail = async () => {
     form.price = pkg.price / 100;
     form.discountPrice = pkg.discountPrice ? pkg.discountPrice / 100 : undefined;
     form.discountType = pkg.discountType;
-    form.gradeLevels = JSON.parse(pkg.gradeLevels || '[]');
 
+    // 加载已选课程包（年级从课程包读取，不可编辑；适用年级自动同步）
     selectedPackages.value = (pkg.packages || []).map((p: any) => ({
       packageId: p.id,
       packageName: p.name,
-      gradeLevel: p.gradeLevels?.[0] || '小班',
+      gradeLevels: Array.isArray(p.gradeLevels) ? p.gradeLevels : (p.gradeLevels ? [p.gradeLevels] : []),
-      sortOrder: p.sortOrder,
+      sortOrder: p.sortOrder ?? 0,
     }));
   } catch (error) {
     message.error('获取套餐详情失败');
@@ -222,12 +235,15 @@ const handleAddPackages = () => {
   const existingIds = new Set(selectedPackages.value.map((p) => p.packageId));
   const newPackages = availablePackages.value
     .filter((p) => selectedRowKeys.value.includes(p.id) && !existingIds.has(p.id))
-    .map((p) => ({
+    .map((p) => {
+      const tags = parseGradeTags(p.gradeTags);
+      return {
         packageId: p.id,
         packageName: p.name,
-      gradeLevel: parseGradeTags(p.gradeTags)?.[0] || '小班',
+        gradeLevels: Array.isArray(tags) && tags.length > 0 ? tags : ['小班'],
         sortOrder: selectedPackages.value.length,
-    }));
+      };
+    });
 
   selectedPackages.value.push(...newPackages);
   selectedRowKeys.value = [];
@@ -267,12 +283,13 @@ const handleSave = async () => {
       id = res.id;  // 后端 Long 序列化为 string
     }
 
-    // 保存课程包关联
+    // 保存课程包关联（按 sortOrder 排序，去重避免唯一约束冲突）
     if (selectedPackages.value.length > 0) {
-      await setCollectionPackages(
+      const sorted = [...selectedPackages.value].sort((a, b) => a.sortOrder - b.sortOrder);
-        id,
+      const packageIds = [...new Map(sorted.map((p) => [p.packageId, p])).values()]
-        selectedPackages.value.map((p) => p.packageId),
+        .sort((a, b) => a.sortOrder - b.sortOrder)
-      );
+        .map((p) => p.packageId);
+      await setCollectionPackages(id, packageIds);
     }
 
     message.success('保存成功');
@@ -303,4 +320,10 @@ onMounted(() => {
 .package-list {
   width: 100%;
 }
+
+.grade-hint {
+  color: #999;
+  font-size: 12px;
+  margin-top: 4px;
+}
 </style>

reading-platform-frontend/src/views/admin/packages/PackageListView.vue

@@ -169,8 +169,19 @@ const statusTexts: Record<string, string> = {
 const getStatusColor = (status: string) => statusColors[status] || 'default';
 const getStatusText = (status: string) => statusTexts[status] || status;
 
-const parseGradeLevels = (gradeLevels: string | string[]) => {
+const parseGradeLevels = (gradeLevels: string | string[] | undefined): string[] => {
-  if (Array.isArray(gradeLevels)) return gradeLevels;
+  if (!gradeLevels) return [];
+  if (Array.isArray(gradeLevels)) {
+    if (gradeLevels.length === 0) return [];
+    if (gradeLevels[0]?.toString().startsWith('[')) {
+      try {
+        return JSON.parse(gradeLevels.join(''));
+      } catch {
+        return [];
+      }
+    }
+    return gradeLevels;
+  }
   try {
     return JSON.parse(gradeLevels || '[]');
   } catch {

reading-platform-java/src/main/java/com/reading/platform/service/CourseCollectionService.java

@@ -222,13 +222,16 @@ public class CourseCollectionService extends ServiceImpl<CourseCollectionMapper,
             throw new BusinessException("课程套餐不存在");
         }
 
+        // 去重：保持首次出现顺序，避免 uk_collection_package 唯一约束冲突
+        List<Long> distinctIds = packageIds.stream().distinct().collect(Collectors.toList());
+
         // 验证课程包是否存在（应用层外键约束）
-        if (!packageIds.isEmpty()) {
+        if (!distinctIds.isEmpty()) {
             List<CoursePackage> packages = packageMapper.selectList(
                     new LambdaQueryWrapper<CoursePackage>()
-                            .in(CoursePackage::getId, packageIds)
+                            .in(CoursePackage::getId, distinctIds)
             );
-            if (packages.size() != packageIds.size()) {
+            if (packages.size() != distinctIds.size()) {
                 throw new BusinessException("存在无效的课程包 ID");
             }
         }
@@ -240,16 +243,16 @@ public class CourseCollectionService extends ServiceImpl<CourseCollectionMapper,
         );
 
         // 创建新的关联
-        for (int i = 0; i < packageIds.size(); i++) {
+        for (int i = 0; i < distinctIds.size(); i++) {
             CourseCollectionPackage association = new CourseCollectionPackage();
             association.setCollectionId(collectionId);
-            association.setPackageId(packageIds.get(i));
+            association.setPackageId(distinctIds.get(i));
             association.setSortOrder(i + 1);
             collectionPackageMapper.insert(association);
         }
 
         // 更新课程包数量（复用前面已验证的 collection 变量）
-        collection.setPackageCount(packageIds.size());
+        collection.setPackageCount(distinctIds.size());
         collectionMapper.updateById(collection);
 
         log.info("课程套餐的课程包设置完成");
@@ -500,6 +503,25 @@ public class CourseCollectionService extends ServiceImpl<CourseCollectionMapper,
         }
     }
 
+    /**
+     * 解析适用年级：数据库存储为 JSON 数组 ["小班","中班","大班"]，需正确解析
+     */
+    private String[] parseGradeLevels(String gradeLevels) {
+        if (!StringUtils.hasText(gradeLevels)) {
+            return new String[0];
+        }
+        try {
+            if (gradeLevels.trim().startsWith("[")) {
+                return JSON.parseArray(gradeLevels, String.class).toArray(new String[0]);
+            }
+            // 兼容旧数据：逗号分隔格式
+            return gradeLevels.split(",");
+        } catch (Exception e) {
+            log.warn("解析 gradeLevels 失败: {}", gradeLevels, e);
+            return new String[0];
+        }
+    }
+
     /**
      * 转换为响应对象
      */
@@ -525,7 +547,7 @@ public class CourseCollectionService extends ServiceImpl<CourseCollectionMapper,
                 .price(collection.getPrice())
                 .discountPrice(collection.getDiscountPrice())
                 .discountType(collection.getDiscountType())
-                .gradeLevels(collection.getGradeLevels() != null ? collection.getGradeLevels().split(",") : new String[0])
+                .gradeLevels(parseGradeLevels(collection.getGradeLevels()))
                 .packageCount(collection.getPackageCount())
                 .status(collection.getStatus())
                 .submittedAt(collection.getSubmittedAt())

reading-platform-java/src/main/java/com/reading/platform/service/impl/CoursePackageServiceImpl.java

@@ -296,24 +296,24 @@ public class CoursePackageServiceImpl extends ServiceImpl<CoursePackageMapper, C
         entity.setIntroMethods(request.getIntroMethods());
         entity.setIntroEvaluation(request.getIntroEvaluation());
         entity.setIntroNotes(request.getIntroNotes());
-        entity.setScheduleRefData(request.getScheduleRefData());
+        entity.setScheduleRefData(emptyToNull(request.getScheduleRefData()));
         entity.setEnvironmentConstruction(request.getEnvironmentConstruction());
         entity.setThemeId(request.getThemeId());
         entity.setPictureBookName(request.getPictureBookName());
-        entity.setEbookPaths(request.getEbookPaths());
+        entity.setEbookPaths(emptyToNull(request.getEbookPaths()));
-        entity.setAudioPaths(request.getAudioPaths());
+        entity.setAudioPaths(emptyToNull(request.getAudioPaths()));
-        entity.setVideoPaths(request.getVideoPaths());
+        entity.setVideoPaths(emptyToNull(request.getVideoPaths()));
-        entity.setOtherResources(request.getOtherResources());
+        entity.setOtherResources(emptyToNull(request.getOtherResources()));
         entity.setPptPath(request.getPptPath());
         entity.setPptName(request.getPptName());
         entity.setPosterPaths(request.getPosterPaths());
         entity.setTools(request.getTools());
         entity.setStudentMaterials(request.getStudentMaterials());
-        entity.setLessonPlanData(request.getLessonPlanData());
+        entity.setLessonPlanData(emptyToNull(request.getLessonPlanData()));
-        entity.setActivitiesData(request.getActivitiesData());
+        entity.setActivitiesData(emptyToNull(request.getActivitiesData()));
-        entity.setAssessmentData(request.getAssessmentData());
+        entity.setAssessmentData(emptyToNull(request.getAssessmentData()));
-        entity.setGradeTags(request.getGradeTags());
+        entity.setGradeTags(emptyToNull(request.getGradeTags()));
-        entity.setDomainTags(request.getDomainTags());
+        entity.setDomainTags(emptyToNull(request.getDomainTags()));
         entity.setHasCollectiveLesson(request.getHasCollectiveLesson() != null && request.getHasCollectiveLesson() ? 1 : 0);
         return entity;
     }
@@ -339,27 +339,34 @@ public class CoursePackageServiceImpl extends ServiceImpl<CoursePackageMapper, C
         if (request.getIntroMethods() != null) entity.setIntroMethods(request.getIntroMethods());
         if (request.getIntroEvaluation() != null) entity.setIntroEvaluation(request.getIntroEvaluation());
         if (request.getIntroNotes() != null) entity.setIntroNotes(request.getIntroNotes());
-        if (request.getScheduleRefData() != null) entity.setScheduleRefData(request.getScheduleRefData());
+        if (request.getScheduleRefData() != null) entity.setScheduleRefData(emptyToNull(request.getScheduleRefData()));
         if (request.getEnvironmentConstruction() != null) entity.setEnvironmentConstruction(request.getEnvironmentConstruction());
         if (request.getThemeId() != null) entity.setThemeId(request.getThemeId());
         if (request.getPictureBookName() != null) entity.setPictureBookName(request.getPictureBookName());
-        if (request.getEbookPaths() != null) entity.setEbookPaths(request.getEbookPaths());
+        if (request.getEbookPaths() != null) entity.setEbookPaths(emptyToNull(request.getEbookPaths()));
-        if (request.getAudioPaths() != null) entity.setAudioPaths(request.getAudioPaths());
+        if (request.getAudioPaths() != null) entity.setAudioPaths(emptyToNull(request.getAudioPaths()));
-        if (request.getVideoPaths() != null) entity.setVideoPaths(request.getVideoPaths());
+        if (request.getVideoPaths() != null) entity.setVideoPaths(emptyToNull(request.getVideoPaths()));
-        if (request.getOtherResources() != null) entity.setOtherResources(request.getOtherResources());
+        if (request.getOtherResources() != null) entity.setOtherResources(emptyToNull(request.getOtherResources()));
         if (request.getPptPath() != null) entity.setPptPath(request.getPptPath());
         if (request.getPptName() != null) entity.setPptName(request.getPptName());
         if (request.getPosterPaths() != null) entity.setPosterPaths(request.getPosterPaths());
         if (request.getTools() != null) entity.setTools(request.getTools());
         if (request.getStudentMaterials() != null) entity.setStudentMaterials(request.getStudentMaterials());
-        if (request.getLessonPlanData() != null) entity.setLessonPlanData(request.getLessonPlanData());
+        if (request.getLessonPlanData() != null) entity.setLessonPlanData(emptyToNull(request.getLessonPlanData()));
-        if (request.getActivitiesData() != null) entity.setActivitiesData(request.getActivitiesData());
+        if (request.getActivitiesData() != null) entity.setActivitiesData(emptyToNull(request.getActivitiesData()));
-        if (request.getAssessmentData() != null) entity.setAssessmentData(request.getAssessmentData());
+        if (request.getAssessmentData() != null) entity.setAssessmentData(emptyToNull(request.getAssessmentData()));
-        if (request.getGradeTags() != null) entity.setGradeTags(request.getGradeTags());
+        if (request.getGradeTags() != null) entity.setGradeTags(emptyToNull(request.getGradeTags()));
-        if (request.getDomainTags() != null) entity.setDomainTags(request.getDomainTags());
+        if (request.getDomainTags() != null) entity.setDomainTags(emptyToNull(request.getDomainTags()));
         if (request.getHasCollectiveLesson() != null) entity.setHasCollectiveLesson(request.getHasCollectiveLesson() ? 1 : 0);
     }
 
+    /**
+     * 将空字符串转为 null，避免 MySQL JSON 列报错 "The document is empty"
+     */
+    private static String emptyToNull(String value) {
+        return StringUtils.hasText(value) ? value : null;
+    }
+
     private CourseLessonResponse toLessonResponse(CourseLesson lesson) {
         List<LessonStep> steps = courseLessonService.findSteps(lesson.getId());
         List<LessonStepResponse> stepResponses = steps.stream()