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解决#4051提出的意见,增加负指数自定义保留位数

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lpj
2025-09-01 18:52:44 +08:00
parent 2d5fcc3b08
commit 73c77aaece
2 changed files with 26 additions and 2 deletions
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20
hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java
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@@ -2549,7 +2549,7 @@ public class NumberUtil {
/**
* 提供精确的幂运算<br>
* 如果n为负数，则返回1/a的-n次方，默认四舍五入
* 如果n为负数，则返回1/a的-n次方，默认四舍五入，保留两位小数
*
* @param number 底数
* @param n 指数，如果为负数，则返回1/a的-n次方
@@ -2557,9 +2557,25 @@ public class NumberUtil {
* @since 4.1.0
*/
public static BigDecimal pow(BigDecimal number, int n) {
return pow(number, n, 2, RoundingMode.HALF_UP);
}
/**
* 提供精确的幂运算<br>
* 如果n为负数，则返回1/a的-n次方，默认四舍五入
*
* @param number 底数
* @param n 指数，如果为负数，则返回1/a的-n次方
* @param scale 保留的小数位 (指数为负数时生效)
* @param roundingMode 保留小数的模式 {@link RoundingMode} (指数为负数时生效)
* @return 幂的积
* @since 4.1.0
*/
public static BigDecimal pow(BigDecimal number, int n, int scale, RoundingMode roundingMode) {
if (n < 0) {
// a的n次方，如果n为负数，则返回1/a的-n次方
return BigDecimal.ONE.divide(pow(number, -n), 2, RoundingMode.HALF_UP);
return BigDecimal.ONE.divide(pow(number, -n), scale, roundingMode);
}
return number.pow(n);
}

8
hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java
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@@ -660,6 +660,14 @@ public class NumberUtilTest {
assertEquals(expected, NumberUtil.pow(number, exponent));
}
@Test
public void testPowSmallNumberScale() {
BigDecimal number = new BigDecimal("1.2");
int exponent = -3;
BigDecimal expected = new BigDecimal("0.58");
assertEquals(expected, NumberUtil.pow(number, exponent));
}
@Test
public void issue3636Test() {
final Number number = NumberUtil.parseNumber("12,234,456");