fix好友列表昵称

mec-biz/src/main/java/com/ym/mec/biz/service/impl/ImUserFriendServiceImpl.java

@@ -154,7 +154,10 @@ public class ImUserFriendServiceImpl extends BaseServiceImpl<Long, ImUserFriend>
                 if (userTypes.size() > 1 || userTypes.contains(ClientEnum.TEACHER.getCode())) {
                     username = Optional.ofNullable(item.getFriend().getRealName()).orElse(username);
                 }
-                item.setFriendNickname(username);
+                // 用户好友默认用户名
+                if (StringUtils.isNotBlank(username)) {
+                    item.setFriendNickname(username);
+                }
             }
         }
         return imUserFriendDtoList;