消息通知添加话题信息 fix

community-service/src/main/java/com/tanpu/community/service/TopicService.java

@@ -82,10 +82,11 @@ public class TopicService {
     }
 
     public String queryTitleById(String topicId) {
-        return topicMapper.selectOne(new LambdaQueryWrapper<TopicEntity>()
+        TopicEntity topicEntity = topicMapper.selectOne(new LambdaQueryWrapper<TopicEntity>()
                 .eq(TopicEntity::getTopicId, topicId)
                 .eq(TopicEntity::getIsConceal, StatusEnum.FALSE)
-                .eq(TopicEntity::getDeleteTag, StatusEnum.FALSE)).getTopicTitle();
+                .eq(TopicEntity::getDeleteTag, StatusEnum.FALSE));
+        return topicEntity!=null?topicEntity.getTopicTitle():null;
     }
 
     public List<TopicEntity> queryByIds(List<String> topicIds) {