注意：对象属性为引用类型

  ctOrders.setCanUseTotal(ArithBigUtil.sub(ctOrders.getCanUseTotal(), coinNum));
  log.info("setCanUseTotal:"+ArithBigUtil.sub(ctOrders.getCanUseTotal(), coinNum));
  ctOrders.setCanuseTotalver(bchange.core.encrypt.EbChangeEncode.encryptKeyMD5
                    (Utils.bigDecimalFormat(ArithBigUtil.sub(ctOrders.getCanUseTotal(), coinNum))));

以上写法是错误的。 ctOrders.setCanUseTotal 被set后，下面 GET后，值就变成新值了。又做了一次减法。
正确的写法

 BigDecimal iCanUseTotal=ArithBigUtil.sub(ctOrders.getCanUseTotal(), coinNum);
  ctOrders.setCanUseTotal(iCanUseTotal);
  log.info("setCanUseTotal:"+iCanUseTotal);
  ctOrders.setCanuseTotalver(bchange.core.encrypt.EbChangeEncode.encryptKeyMD5
                    (Utils.bigDecimalFormat(iCanUseTotal)));