java中对数字的精确运算使用类BigDecimal（转）

左手的ㄟ右手 2022-05-20 04:12 177阅读 0赞

原文：[https://www.cnblogs.com/lovelyYakir/p/6290299.html][https_www.cnblogs.com_lovelyYakir_p_6290299.html]

public class CalculateUtils { 
        /** * 加法 * * @param var1 * @param var2 * @return */
        public static double add(double var1, double var2) {
            BigDecimal b1 = new BigDecimal(Double.toString(var1));
            BigDecimal b2 = new BigDecimal(Double.toString(var2));
            return b1.add(b2).doubleValue();
    
        }
    
        /** * 减法 * * @param var1 * @param var2 * @return */
    
        public static double sub(double var1, double var2) {
            BigDecimal b1 = new BigDecimal(Double.toString(var1));
            BigDecimal b2 = new BigDecimal(Double.toString(var2));
            return b1.subtract(b2).doubleValue();
        }
    
        /** * 乘法 * * @param var1 * @param var2 * @return */
        public static double mul(double var1, double var2) {
            BigDecimal b1 = new BigDecimal(Double.toString(var1));
            BigDecimal b2 = new BigDecimal(Double.toString(var2));
            return b1.multiply(b2).doubleValue();
        }
    
        /** * 除法 * * @param v1 * @param v2 * @param scale 精度，到小数点后几位 * @return */
    
        public static double div(double v1, double v2, int scale) {
    
            if (scale < 0) {
    
                throw new IllegalArgumentException("The scale must be a positive integer or ");
    
            }
            BigDecimal b1 = new BigDecimal(Double.toString(v1));
            BigDecimal b2 = new BigDecimal(Double.toString(v2));
            return b1.divide(b2, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
    
        }
    
        /** * 四舍五入 * @param v * @param scale 精确位数 * @return */
        public static double round(double v, int scale) {
    
            if (scale < 0) {
    
                throw new IllegalArgumentException("The scale must be a positive integer or zero");
    
            }
    
            BigDecimal b = new BigDecimal(Double.toString(v));
    
            BigDecimal one = new BigDecimal("1");
    
            return b.divide(one, scale, BigDecimal.ROUND_HALF_UP).doubleValue();
    
        }
    }

[https_www.cnblogs.com_lovelyYakir_p_6290299.html]: https://www.cnblogs.com/lovelyYakir/p/6290299.html