fix:没学生不开好友

cooleshow-user/user-biz/src/main/java/com/yonge/cooleshow/biz/dal/service/impl/ImUserFriendServiceImpl.java

@@ -75,6 +75,9 @@ public class ImUserFriendServiceImpl extends ServiceImpl<ImUserFriendDao, ImUser
     @Override
     @Transactional(rollbackFor = Exception.class)
     public void saveUserFriend(Long teacherId, Set<Long> studentIds) {
+        if (CollectionUtils.isEmpty(studentIds)) {
+            return;
+        }
         Date now = new Date();
         //老师添加学员联系人
         List<ImUserFriend> imUserFriends = new ArrayList<>();