jdk工具类____bigdecimal精度运算工具类

package com.cctin.platform.util;

import java.math.BigDecimal;

public class MathUtil {
	
	 /**
	  * @info:加法运算
	  */
	 public static double add(double v1, double v2) {
		 BigDecimal b1 = new BigDecimal(Double.toString(v1));
		 BigDecimal b2 = new BigDecimal(Double.toString(v2));
		 return b1.add(b2).doubleValue();
	 }
	 /**
	  * @info:减法运算
	  */
	 public static double subtract(double v1, double v2) {
	  BigDecimal b1 = new BigDecimal(Double.toString(v1));
	  BigDecimal b2 = new BigDecimal(Double.toString(v2));
	  return b1.subtract(b2).doubleValue();
	 }

	 /**
	  * @info:乘法运算
	  */
	 public static double multiply(double v1, double v2,int scale) {
		  BigDecimal b1 = new BigDecimal(Double.toString(v1));
		  BigDecimal b2 = new BigDecimal(Double.toString(v2));
		  return b1.multiply(b2).doubleValue();
	 }

	 /**
	  * @info:除法运算
	  * 除不尽保留
	  */
	public static double divide(double v1, double v2) {
		//默认采用保留10位小数
		int DEF_DIV_SCALE = 10;
		BigDecimal b1 = new BigDecimal(Double.toString(v1));
		BigDecimal b2 = new BigDecimal(Double.toString(v2));
		return b1.divide(b2, DEF_DIV_SCALE, BigDecimal.ROUND_HALF_UP).doubleValue();
	}
	
	
	/**
	 * @info:精度运算 :四舍五入
	 */
	public static double accuracyRoundHalfUp(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();
	}
	/**
	 * @info:精度运算 :四舍五入
	 */
	public static double accuracyRoundDown(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_DOWN).doubleValue();
	}
//======================test==================\\
	public static void main(String[] args) {
		//1.加法计算
		System.out.println("加法计算____:"+add(2, 3.9));
		//2.减法计算
		System.out.println("加法计算____:"+subtract(2.67,1.67));
		//3.乘法计算保留2位小数
		System.out.println("乘法计算____:"+multiply(2.3, 4.56, 2));
		//4.除法运算
		System.out.println("除法运算____:"+divide(6.67, 2.1));
		//5.精度运算:四舍五入
		System.out.println("精度_四舍五入_:"+accuracyRoundHalfUp(3.349, 2));
		//6.精度运算:直接舍去
		System.out.println("精度_直接舍去_:"+accuracyRoundDown(3.349, 2));
	}
}

//运行结果