Double firstTotalMileage = NumberKit.toDouble(record.getString("totalmil"));//我还得自己转一下
Double lastTotalMileage = NumberKit.toDouble(record.getString("totalmil"));

Double mileage = (lastTotalMileage - firstTotalMileage);

Integer firstTotalCharge = record.getInt("cdcs");//这个就方便了
Integer lastTotalCharge = record.getInt("cdcs");