一、BigDecimal类

在Java中，BigDecimal类提供了对超过16位有效位的数进行精确运算的能力。它不能直接使用传统的+、-、*、/等算术运算符，而是必须调用其相应的方法来进行运算。这些方法包括

加法：使用add()方法。
减法：使用subtract()方法。
乘法：使用multiply()方法。
除法：使用divide()方法，该方法允许设置精确度和舍入模式来控制计算结果的精度和舍入规则。

二、工具类

代码如下：

package com.common.utils;import org.apache.commons.lang3.ObjectUtils;
import java.math.BigDecimal;/*** BigDecimal工具类*/
public class BigDecimalUtils {private static final BigDecimal hundred = new BigDecimal(100);private static final BigDecimal thousand = new BigDecimal(10000);/*** 转换String保留2位*/public static String genTransString(BigDecimal num) {if (num == null) {num = BigDecimal.ZERO;} else {num = num.setScale(2,BigDecimal.ROUND_HALF_UP);}return num.stripTrailingZeros().toPlainString();}/*** 转换为亿元保留2位,返回String*/public static String genMillon(BigDecimal num) {if (num == null) {num = BigDecimal.ZERO;} else {num = num.divide(thousand,2,BigDecimal.ROUND_HALF_UP);}return num.stripTrailingZeros().toPlainString();}/*** 相除，转换为亿元保留2位,返回String*/public static String genMillonTwo(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}if (compare(num2)) {return BigDecimal.ZERO.toPlainString();} else {num1 = num1.divide(thousand,4,BigDecimal.ROUND_HALF_UP);num2 = num2.divide(thousand,4,BigDecimal.ROUND_HALF_UP);return num1.divide(num2,2,BigDecimal.ROUND_HALF_UP).multiply(new BigDecimal(100)).stripTrailingZeros().toPlainString();}}/*** String类型的万元转换为亿元* @return*/public static String genMillonString(String num) {BigDecimal bd;if (ObjectUtils.isNotEmpty(num)) {bd = new BigDecimal(num);} else {bd = BigDecimal.ZERO;}return bd.divide(thousand,2,BigDecimal.ROUND_HALF_UP).stripTrailingZeros().toPlainString();}/*** 相加之和，且四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genAddNum(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}return num1.add(num2).setScale(2,BigDecimal.ROUND_HALF_UP);}/*** 相减之差，且四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genSubtractNum(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}return num1.subtract(num2).setScale(2,BigDecimal.ROUND_HALF_UP);}/*** 相乘之积，且四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genMultiplyNum(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}if (compare(num2)) {return BigDecimal.ZERO;} else {return num1.multiply(num2).setScale(2,BigDecimal.ROUND_HALF_UP);}}/*** int类型数相乘，且四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genIntMultiplyNum(Integer num1, Integer num2) {if (num1 == null) {num1 = 0;}if (num2 == null) {num2 = 0;}if (num2.intValue() == 0) {return BigDecimal.ZERO;} else {return new BigDecimal(num1).multiply(new BigDecimal(num2)).setScale(2,BigDecimal.ROUND_HALF_UP);}}/*** 两数相除，且四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genDivideNum(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}if (compare(num2)) {return BigDecimal.ZERO;} else {return num1.divide(num2,4,BigDecimal.ROUND_HALF_UP);}}/*** 两数相除，且乘100，四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genBigDecimalNum(BigDecimal num1, BigDecimal num2) {if (num1 == null) {num1 = BigDecimal.ZERO;}if (num2 == null) {num2 = BigDecimal.ZERO;}if (compare(num2)) {return BigDecimal.ZERO;} else {return num1.divide(num2,4,BigDecimal.ROUND_HALF_UP).multiply(hundred).setScale(2,BigDecimal.ROUND_HALF_UP);}}/*** 两个int类型数相除，且乘100，四舍五入，保留两位小数，最后转为String类型* @param num1* @param num2* @return*/public static String genIntToStringNum(Integer num1, Integer num2) {if (num1 == null) {num1 = 0;}if (num2 == null) {num2 = 0;}if (num2.intValue() == 0) {return BigDecimal.ZERO.toPlainString();} else {return new BigDecimal(num1).divide(new BigDecimal(num2),4,BigDecimal.ROUND_HALF_UP).multiply(hundred).setScale(2,BigDecimal.ROUND_HALF_UP).stripTrailingZeros().toPlainString();}}/*** 两个int类型数相除，且乘100，四舍五入，保留两位小数* @param num1* @param num2* @return*/public static BigDecimal genIntToBigDecimalNum(Integer num1, Integer num2) {if (num1 == null) {num1 = 0;}if (num2 == null) {num2 = 0;}if (num2.intValue() == 0) {return BigDecimal.ZERO;} else {return new BigDecimal(num1).divide(new BigDecimal(num2),4,BigDecimal.ROUND_HALF_UP).multiply(hundred).setScale(2,BigDecimal.ROUND_HALF_UP);}}/*** 与0相比较，是否相等* @param num* @return*/public static Boolean compare(BigDecimal num) {if (num.compareTo(BigDecimal.ZERO) == 0 ) {return true;} else {return false;}}}