fix bug

mallinkService/src/main/java/com/iformall/service/park/impl/etcp/EtcpHelper.java

@@ -339,6 +339,9 @@ public class EtcpHelper {
         String businessId;
         WxMerchant wxMerchant = wxMerchantService.getById(merchantId);
         String carParams = wxMerchant.getCarParams();
+        if (StringUtils.isBlank(carParams)) {
+        	return null;
+        }
         JSONObject objParams1 = JSON.parseObject(carParams);
         businessId = objParams1.getString("businessId");
         return businessId;