Java 使用 bigdecimal 计算除以 3 到百

Question

这是我计算金额百分比的示例代码，在给定的示例中，我希望 return 为 10，但它给了我 9.9。我如何四舍五入到 10？

import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;


public class Test {


    public static final int AMOUNT_SCALE = 2;
    public static final int PRECISION_SIX = 6;
    private static BigDecimal tmp = new BigDecimal("100");
    public static final BigDecimal ONE_HUNDRED = tmp.setScale(0, RoundingMode.DOWN);
    public static final MathContext MATH_CONTEXT = new MathContext(PRECISION_SIX, RoundingMode.HALF_UP);

    public  static void main(String [] args){
         System.out.println(multiplyTwoNumbersAndDivideByOneHundredAmount(new BigDecimal(30), new BigDecimal(33.33))); ;
    }

    public static BigDecimal multiplyTwoNumbersAndDivideByOneHundredAmount(BigDecimal firstNumber, BigDecimal secondNumber) {
        return (firstNumber.multiply(secondNumber)).divide(ONE_HUNDRED,MATH_CONTEXT).setScale(AMOUNT_SCALE,RoundingMode.DOWN);
    }
}

Answer 1

.setScale(0, RoundingMode.HALF_UP);

是您要找的。

Answer 2

通过 BigInteger 对象传递结果：

BigInteger bi = new BigInteger(tmp);

Java 使用 bigdecimal 计算除以 3 到百

Java calculation divisible by 3 to hundred using bigdecimal

java

bigdecimal