public String oderCode(){
        String orderBgegin="DD";
        String orderCode = "";//表中存在的最大订单号
        Calendar cal = Calendar.getInstance();
        int day1 = cal.get(Calendar.DATE);
        String day = String.valueOf(cal.get(Calendar.DATE)).format("%02d", day1);//当前日
        int month1 = cal.get(Calendar.MONTH) + 1;
        String month = String.valueOf(cal.get(Calendar.MONTH) + 1).format("%02d", month1);//当前月
        String year = String.valueOf(cal.get(Calendar.YEAR));//当前年
        String oldday = "";//最大订单号中日
        String oldmonth = "";//最大订单号中日月
        String oldyear = "";//最大订单号中日年
        String oldnum = "";
        //查出数据库中最大的订单号
        ComponentOrder componentOrder=componentOrderMapper.selectList(new QueryWrapper<ComponentOrder>().select("order_code").last("order by create_time desc")).get(0);
        //截取订单号中年月日
        orderCode = componentOrder.getOrderCode();
        oldyear = orderCode.substring(2,6);
        oldmonth = orderCode.substring(6,8);
        oldday = orderCode.substring(8,10);
        oldnum = orderCode.substring(10);
        //判断是否当天最新订单，进行拼接
        if(month.equals(oldmonth) && day.equals(oldday) && year.equals(oldyear)){
            AtomicInteger val = new AtomicInteger(Integer.valueOf(oldnum));
            int nextVal = val.incrementAndGet();
            String i = String.format("%04d", nextVal);
            orderCode = orderBgegin+oldyear+oldmonth+day+i;
        }else{
            orderCode = orderBgegin+year+month+day+"0000";
        }
        return orderCode;
    }