optimize the refund amount

src/main/java/com/ctrip/fun/admin/controller/order/OpEventActivityOrderController.java

@@ -445,7 +445,11 @@ public class OpEventActivityOrderController extends AbstractOpOrderController<Ev
             	processBean.setPlayerNum(playerNum.trim());
             }
             BigDecimal refundTotalAmount = orderBean.getPrePayCardRefundAmount().add(orderBean.getRefundAmount());
-            BigDecimal requestTotalAmount = BigDecimal.valueOf(Double.parseDouble(refundAmount)).add(BigDecimal.valueOf(Double.parseDouble(prePayCardRefundAmount)));
+            BigDecimal requestTotalAmount = new BigDecimal(0);
+            if(StringUtils.isEmpty(refundAmount) && StringUtils.isEmpty(prePayCardRefundAmount)){
+            	requestTotalAmount = BigDecimal.valueOf(Double.parseDouble(refundAmount)).add(BigDecimal.valueOf(Double.parseDouble(prePayCardRefundAmount)));
+            }
+            
             BigDecimal enableRefundAmount = orderBean.getPrePayAmount().subtract(orderBean.getVoucherAmount());
             if(requestTotalAmount.add(refundTotalAmount).compareTo(enableRefundAmount)==1){
             	map.addAttribute("message", "退款金额超出限制！");