public static int multiply(double num1, double num2) {
        BigDecimal num1Bd = new BigDecimal(Double.toString(num1));
        BigDecimal num2Bd = new BigDecimal(Double.toString(num2));
        MathContext mathContext = new MathContext(num1Bd.precision(), RoundingMode.HALF_UP);
        return num1Bd.multiply(num2Bd, mathContext).intValue();
    }
public static int multiply ( double num1 , double num2 ) { BigDecimal num1Bd = new BigDecimal ( Double . toString ( num1 ) ) ; BigDecimal num2Bd = new BigDecimal ( Double . toString ( num2 ) ) ; MathContext mathContext = new MathContext ( num1Bd . precision ( ) , RoundingMode . HALF_UP ) ; return num1Bd . multiply ( num2Bd , mathContext ) . intValue ( ) ; }
将double与小数相乘，计算结四舍五入保留整数位。

@param num1 数字1
@param num2 数字2
@return 数字相乘计算结果