BigDecimal乘法

BigDecimal result = new BigDecimal(doubleValue).multiply(factor2);

public class Payment
 {
     BigDecimal itemCost;
     BigDecimal totalCost; // You can initialize it if you wish.

     public BigDecimal calculateCost(int itemQuantity, BigDecimal itemPrice)
     {
         itemCost  = itemPrice.multiply(new BigDecimal(itemQuantity));
         totalCost = totalCost.add(itemCost);
         return totalCost;
     }
 }