增加主学习内容，修改学习项目、学习内容新建的逻辑

src/main/java/cn/chnmuseum/party/web/controller/LearningProjectController.java

@@ -138,8 +138,15 @@ public class LearningProjectController extends BaseController {
                 // 查询子学习内容中被删除的版权方信息
                 List<CopyrightOwner> copyrightOwners = this.copyrightOwnerService.listByIds(list1);
                 StringBuilder stringBuilder = new StringBuilder();
-                copyrightOwners.forEach(s -> stringBuilder.append(s.getName()+ "、"));
-                return getFailResult("展板版权方：" + stringBuilder + "。被子学习内容使用，不能被删除，更新失败！");
+                copyrightOwners.forEach(s -> {
+                    stringBuilder.append(s.getName());
+                    if (copyrightOwners.get(copyrightOwners.size() - 1).equals(s)) {
+                        stringBuilder.append("，");
+                    }else{
+                        stringBuilder.append("、");
+                    }
+                });
+                return getFailResult("展板版权方：" + stringBuilder + "被子学习内容使用，不能被删除，更新失败！");
             }
 
             // 查询子学习内容的展板分类
@@ -154,8 +161,15 @@ public class LearningProjectController extends BaseController {
                 // 查询被删除的展板分类信息
                 List<ExhibitionBoardCat> learningContentBoardCats = this.exhibitionBoardCatService.listByIds(list2);
                 StringBuilder stringBuilder = new StringBuilder();
-                learningContentBoardCats.forEach(s -> stringBuilder.append(s.getName()));
-                return getFailResult("展板类别：" + stringBuilder + "。被子学习内容使用，不能被删除，更新失败");
+                learningContentBoardCats.forEach(s -> {
+                    stringBuilder.append(s.getName());
+                    if (learningContentBoardCats.get(learningContentBoardCats.size() - 1).equals(s)) {
+                        stringBuilder.append("，");
+                    }else{
+                        stringBuilder.append("、");
+                    }
+                });
+                return getFailResult("展板类别：" + stringBuilder + "被子学习内容使用，不能被删除，更新失败");
             }
 
             // 查询子学习内容的展板
@@ -166,13 +180,18 @@ public class LearningProjectController extends BaseController {
             // 修改主要学习内容时删除了子学习内容所使用展板
             if (CollectionUtil.isNotEmpty(list3) && !learningProject.getExhibitionBoardIdList().containsAll(list3)) {
                 // 差集
-                list3.retainAll(learningProject.getExhibitionBoardIdList());
+                list3.removeAll(learningProject.getExhibitionBoardIdList());
                 // 查询被删除的展板信息
                 List<ExhibitionBoard> exhibitionBoards = this.exhibitionBoardService.listByIds(list3);
                 StringBuilder stringBuilder = new StringBuilder();
-                exhibitionBoards.forEach(s -> stringBuilder.append(s.getName()));
-
-                return getFailResult("展板：" + stringBuilder + "。被子学习内容使用，不能被删除，更新失败！");
+                exhibitionBoards.forEach(s -> {
+                    stringBuilder.append(s.getName());
+                    if (exhibitionBoards.get(exhibitionBoards.size() - 1).equals(s)) {
+                        stringBuilder.append("，");
+                    }else{
+                        stringBuilder.append("、");
+                    }});
+                return getFailResult("展板：" + stringBuilder + "被子学习内容使用，不能被删除，更新失败！");
             }
         }