加减乘除工具类BigDecimalUtil

场景：为毛要用BigDecimal这个类来实现加减乘除呢？我不说其他的，你去用小数乘小数，除小数就知道。话不多说，老规矩，开箱即用。

BigDecimalUtil.java

package com.mmall.util;

import java.math.BigDecimal;

/**
 * Created by 敲代码的卡卡罗特
 */
public class BigDecimalUtil {

    private BigDecimalUtil(){

    }

    public static BigDecimal add(double v1,double v2){
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.add(b2);
    }

    public static BigDecimal sub(double v1,double v2){
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.subtract(b2);
    }

    public static BigDecimal mul(double v1,double v2){
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.multiply(b2);
    }

    public static BigDecimal div(double v1,double v2){
        BigDecimal b1 = new BigDecimal(Double.toString(v1));
        BigDecimal b2 = new BigDecimal(Double.toString(v2));
        return b1.divide(b2,2,BigDecimal.ROUND_HALF_UP);//四舍五入,保留2位小数

        //除不尽的情况
    }

}