fix 替换异常报错

netflix-service/src/main/java/com/cyksj/service/relation/impl/GroupRelationFrontServiceImpl.java

@@ -1555,6 +1555,9 @@ public class GroupRelationFrontServiceImpl implements GroupRelationFrontService
 			}
 			//替换车票
 			TicketChangeDto changeDto = getTicketAndGenerateOrder(userId, skuId, null, null);
+			if (changeDto == null) {
+				throw BusinessRuntimeException.getInstance("系统繁忙，请重试");
+			}
 			//替换记录
 			NetflixUserChangeOtherTicketRecord changeOtherTicketRecord = new NetflixUserChangeOtherTicketRecord();
 			changeOtherTicketRecord.setUserId(userId);