使用bigdecimal [重复]将Java计算整除3到100(Java calculation divisible by 3 to hundred using bigdecimal [duplicate])

 
 
 这个问题在这里已有答案： 
 
 
 
  
 Java BigDecimal：舍入到最接近的整数值 6个答案 
 
 
 
 
 这是我的示例代码，它计算金额的百分比，在给定的例子中，我期望返回为10，但它给我9.9。 我如何将其四舍五入？ 
 
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);
    }
}

 
 
This question already has an answer here:
 
 
 
  
 Java BigDecimal: Round to the nearest whole value  6 answers  
 
 
 
 
Here is my sample code which calculates the percentage of amounts, in the given example i am expecting the return to be 10 but its giving me 9.9. how do i round it up to 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);
    }
}

原文：https://stackoverflow.com/questions/41124008