diff --git a/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java b/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java
index 3afbec7f3..2f0f95a5e 100644
--- a/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java
@@ -43,6 +43,14 @@ public class NumberUtil {
*/
private static final int DEFAUT_DIV_SCALE = 10;
+ /**
+ * 0-20对应的阶乘，超过20的阶乘会超过Long.MAX_VALUE
+ */
+ private static final long[] FACTORIALS = new long[]{
+ 1L, 1L, 2L, 6L, 24L, 120L, 720L, 5040L, 40320L, 362880L, 3628800L, 39916800L, 479001600L, 6227020800L,
+ 87178291200L, 1307674368000L, 20922789888000L, 355687428096000L, 6402373705728000L, 121645100408832000L,
+ 2432902008176640000L};
+
/**
* 提供精确的加法运算
*
@@ -1422,28 +1430,50 @@ public class NumberUtil {
* @return 结果
* @since 4.1.0
*/
- public static long factorial(long start, long end) {
- if (0L == start || start == end) {
- return 1L;
- }
- if (start < end) {
- return 0L;
- }
- return start * factorial(start - 1, end);
- }
-
+ public static long factorial(long start, long end) {
+ // 负数没有阶乘
+ if(start < 0 || end < 0) {
+ throw new IllegalArgumentException(String.format("Factorial start and end both must be >= 0, " +
+ "but got start=%d, end=%d", start, end));
+ }
+ if (0L == start || start == end) {
+ return 1L;
+ }
+ if (start < end) {
+ return 0L;
+ }
+ return factorialMultiplyAndCheck(start, factorial(start - 1, end));
+ }
+
/**
- * 计算阶乘
- *
- * n! = n * (n-1) * ... * 2 * 1
- *
- *
- * @param n 阶乘起始
- * @return 结果
- */
- public static long factorial(long n) {
- return factorial(n, 1);
- }
+ * 计算范围阶乘中校验中间的计算是否存在溢出，factorial提前做了负数和0的校验，因此这里没有校验数字的正负
+ * @param a 乘数
+ * @param b 被乘数
+ * @return 如果 a * b的结果没有溢出直接返回，否则抛出异常
+ */
+ private static long factorialMultiplyAndCheck(long a, long b) {
+ if (a <= Long.MAX_VALUE / b) {
+ return a * b;
+ }
+ throw new IllegalArgumentException(String.format("Overflow in multiplication: {%d} * {%d}", a, b));
+ }
+
+ /**
+ * 计算阶乘
+ *
+ * n! = n * (n-1) * ... * 2 * 1
+ *
+ *
+ * @param n 阶乘起始
+ * @return 结果
+ */
+ public static long factorial(long n) {
+ if (n < 0 || n > 20) {
+ throw new IllegalArgumentException(String.format("Factorial must have n >= 0 and n <= 20 for n!, " +
+ "but got n = %d", n));
+ }
+ return FACTORIALS[(int) n];
+ }
/**
* 平方根算法
diff --git a/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java
index 100336c3c..dd1710807 100644
--- a/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java
@@ -1,267 +1,272 @@
-package cn.hutool.core.util;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import java.math.BigDecimal;
-import java.math.RoundingMode;
-
-/**
- * {@link NumberUtil} 单元测试类
- *
- * @author Looly
- *
- */
-public class NumberUtilTest {
-
- @Test
- public void addTest() {
- Float a = 3.15f;
- Double b = 4.22;
- double result = NumberUtil.add(a, b).doubleValue();
- Assert.assertEquals(7.37, result, 2);
- }
-
- @Test
- public void addTest2() {
- double a = 3.15f;
- double b = 4.22;
- double result = NumberUtil.add(a, b);
- Assert.assertEquals(7.37, result, 2);
- }
-
- @Test
- public void addTest3() {
- float a = 3.15f;
- double b = 4.22;
- double result = NumberUtil.add(a, b, a, b).doubleValue();
- Assert.assertEquals(14.74, result, 2);
- }
-
- @Test
- public void addTest4() {
- BigDecimal result = NumberUtil.add(new BigDecimal("133"), new BigDecimal("331"));
- Assert.assertEquals(new BigDecimal("464"), result);
- }
-
- @Test
- public void isIntegerTest() {
- Assert.assertTrue(NumberUtil.isInteger("-12"));
- Assert.assertTrue(NumberUtil.isInteger("256"));
- Assert.assertTrue(NumberUtil.isInteger("0256"));
- Assert.assertTrue(NumberUtil.isInteger("0"));
- Assert.assertFalse(NumberUtil.isInteger("23.4"));
- }
-
- @Test
- public void isLongTest() {
- Assert.assertTrue(NumberUtil.isLong("-12"));
- Assert.assertTrue(NumberUtil.isLong("256"));
- Assert.assertTrue(NumberUtil.isLong("0256"));
- Assert.assertTrue(NumberUtil.isLong("0"));
- Assert.assertFalse(NumberUtil.isLong("23.4"));
- }
-
- @Test
- public void isNumberTest() {
- Assert.assertTrue(NumberUtil.isNumber("28.55"));
- Assert.assertTrue(NumberUtil.isNumber("0"));
- Assert.assertTrue(NumberUtil.isNumber("+100.10"));
- Assert.assertTrue(NumberUtil.isNumber("-22.022"));
- Assert.assertTrue(NumberUtil.isNumber("0X22"));
- }
-
- @Test
- public void divTest() {
- double result = NumberUtil.div(0, 1);
- Assert.assertEquals(0.0, result, 0);
- }
-
- @Test
- public void roundTest() {
-
- // 四舍
- String round1 = NumberUtil.roundStr(2.674, 2);
- String round2 = NumberUtil.roundStr("2.674", 2);
- Assert.assertEquals("2.67", round1);
- Assert.assertEquals("2.67", round2);
-
- // 五入
- String round3 = NumberUtil.roundStr(2.675, 2);
- String round4 = NumberUtil.roundStr("2.675", 2);
- Assert.assertEquals("2.68", round3);
- Assert.assertEquals("2.68", round4);
-
- // 四舍六入五成双
- String round31 = NumberUtil.roundStr(4.245, 2, RoundingMode.HALF_EVEN);
- String round41 = NumberUtil.roundStr("4.2451", 2, RoundingMode.HALF_EVEN);
- Assert.assertEquals("4.24", round31);
- Assert.assertEquals("4.25", round41);
-
- // 补0
- String round5 = NumberUtil.roundStr(2.6005, 2);
- String round6 = NumberUtil.roundStr("2.6005", 2);
- Assert.assertEquals("2.60", round5);
- Assert.assertEquals("2.60", round6);
-
- // 补0
- String round7 = NumberUtil.roundStr(2.600, 2);
- String round8 = NumberUtil.roundStr("2.600", 2);
- Assert.assertEquals("2.60", round7);
- Assert.assertEquals("2.60", round8);
- }
-
- @Test
- public void roundStrTest() {
- String roundStr = NumberUtil.roundStr(2.647, 2);
- Assert.assertEquals(roundStr, "2.65");
- }
-
- @Test
- public void roundHalfEvenTest() {
- String roundStr = NumberUtil.roundHalfEven(4.245, 2).toString();
- Assert.assertEquals(roundStr, "4.24");
- roundStr = NumberUtil.roundHalfEven(4.2450, 2).toString();
- Assert.assertEquals(roundStr, "4.24");
- roundStr = NumberUtil.roundHalfEven(4.2451, 2).toString();
- Assert.assertEquals(roundStr, "4.25");
- roundStr = NumberUtil.roundHalfEven(4.2250, 2).toString();
- Assert.assertEquals(roundStr, "4.22");
-
- roundStr = NumberUtil.roundHalfEven(1.2050, 2).toString();
- Assert.assertEquals(roundStr, "1.20");
- roundStr = NumberUtil.roundHalfEven(1.2150, 2).toString();
- Assert.assertEquals(roundStr, "1.22");
- roundStr = NumberUtil.roundHalfEven(1.2250, 2).toString();
- Assert.assertEquals(roundStr, "1.22");
- roundStr = NumberUtil.roundHalfEven(1.2350, 2).toString();
- Assert.assertEquals(roundStr, "1.24");
- roundStr = NumberUtil.roundHalfEven(1.2450, 2).toString();
- Assert.assertEquals(roundStr, "1.24");
- roundStr = NumberUtil.roundHalfEven(1.2550, 2).toString();
- Assert.assertEquals(roundStr, "1.26");
- roundStr = NumberUtil.roundHalfEven(1.2650, 2).toString();
- Assert.assertEquals(roundStr, "1.26");
- roundStr = NumberUtil.roundHalfEven(1.2750, 2).toString();
- Assert.assertEquals(roundStr, "1.28");
- roundStr = NumberUtil.roundHalfEven(1.2850, 2).toString();
- Assert.assertEquals(roundStr, "1.28");
- roundStr = NumberUtil.roundHalfEven(1.2950, 2).toString();
- Assert.assertEquals(roundStr, "1.30");
- }
-
- @Test
- public void decimalFormatTest() {
- long c = 299792458;// 光速
-
- String format = NumberUtil.decimalFormat(",###", c);
- Assert.assertEquals("299,792,458", format);
- }
-
- @Test
- public void decimalFormatMoneyTest() {
- double c = 299792400.543534534;
-
- String format = NumberUtil.decimalFormatMoney(c);
- Assert.assertEquals("299,792,400.54", format);
-
- double value = 0.5;
- String money = NumberUtil.decimalFormatMoney(value);
- Assert.assertEquals("0.50", money);
- }
-
- @Test
- public void equalsTest() {
- Assert.assertTrue(NumberUtil.equals(new BigDecimal("0.00"), BigDecimal.ZERO));
- }
-
- @Test
- public void formatPercentTest() {
- String str = NumberUtil.formatPercent(0.33543545, 2);
- Assert.assertEquals("33.54%", str);
- }
-
- @Test
- public void toBigDecimalTest() {
- double a = 3.14;
-
- BigDecimal bigDecimal = NumberUtil.toBigDecimal(a);
- Assert.assertEquals("3.14", bigDecimal.toString());
- }
-
- @Test
- public void maxTest() {
- int max = NumberUtil.max(5,4,3,6,1);
- Assert.assertEquals(6, max);
- }
-
- @Test
- public void minTest() {
- int min = NumberUtil.min(5,4,3,6,1);
- Assert.assertEquals(1, min);
- }
-
- @Test
- public void parseIntTest() {
- int v1 = NumberUtil.parseInt("0xFF");
- Assert.assertEquals(255, v1);
- int v2 = NumberUtil.parseInt("010");
- Assert.assertEquals(10, v2);
- int v3 = NumberUtil.parseInt("10");
- Assert.assertEquals(10, v3);
- int v4 = NumberUtil.parseInt(" ");
- Assert.assertEquals(0, v4);
- int v5 = NumberUtil.parseInt("10F");
- Assert.assertEquals(10, v5);
- int v6 = NumberUtil.parseInt("22.4D");
- Assert.assertEquals(22, v6);
-
- int v7 = NumberUtil.parseInt("0");
- Assert.assertEquals(0, v7);
- }
-
- @Test
- public void parseLongTest() {
- long v1 = NumberUtil.parseLong("0xFF");
- Assert.assertEquals(255L, v1);
- long v2 = NumberUtil.parseLong("010");
- Assert.assertEquals(10L, v2);
- long v3 = NumberUtil.parseLong("10");
- Assert.assertEquals(10L, v3);
- long v4 = NumberUtil.parseLong(" ");
- Assert.assertEquals(0L, v4);
- long v5 = NumberUtil.parseLong("10F");
- Assert.assertEquals(10L, v5);
- long v6 = NumberUtil.parseLong("22.4D");
- Assert.assertEquals(22L, v6);
- }
-
- @Test
- public void factorialTest(){
- long factorial = NumberUtil.factorial(0);
- Assert.assertEquals(1, factorial);
-
- factorial = NumberUtil.factorial(5, 0);
- Assert.assertEquals(120, factorial);
- factorial = NumberUtil.factorial(5, 1);
- Assert.assertEquals(120, factorial);
-
- Assert.assertEquals(5, NumberUtil.factorial(5, 4));
- }
-
- @Test
- public void mulTest(){
- final BigDecimal mul = NumberUtil.mul(new BigDecimal("10"), null);
- Assert.assertEquals(BigDecimal.ZERO, mul);
- }
-
-
- @Test
- public void isPowerOfTwoTest() {
- Assert.assertEquals(false, NumberUtil.isPowerOfTwo(-1));
- Assert.assertEquals(true, NumberUtil.isPowerOfTwo(16));
- Assert.assertEquals(true, NumberUtil.isPowerOfTwo(65536));
- Assert.assertEquals(true, NumberUtil.isPowerOfTwo(1));
- Assert.assertEquals(false, NumberUtil.isPowerOfTwo(17));
- }
-}
+package cn.hutool.core.util;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+/**
+ * {@link NumberUtil} 单元测试类
+ *
+ * @author Looly
+ *
+ */
+public class NumberUtilTest {
+
+ @Test
+ public void addTest() {
+ Float a = 3.15f;
+ Double b = 4.22;
+ double result = NumberUtil.add(a, b).doubleValue();
+ Assert.assertEquals(7.37, result, 2);
+ }
+
+ @Test
+ public void addTest2() {
+ double a = 3.15f;
+ double b = 4.22;
+ double result = NumberUtil.add(a, b);
+ Assert.assertEquals(7.37, result, 2);
+ }
+
+ @Test
+ public void addTest3() {
+ float a = 3.15f;
+ double b = 4.22;
+ double result = NumberUtil.add(a, b, a, b).doubleValue();
+ Assert.assertEquals(14.74, result, 2);
+ }
+
+ @Test
+ public void addTest4() {
+ BigDecimal result = NumberUtil.add(new BigDecimal("133"), new BigDecimal("331"));
+ Assert.assertEquals(new BigDecimal("464"), result);
+ }
+
+ @Test
+ public void isIntegerTest() {
+ Assert.assertTrue(NumberUtil.isInteger("-12"));
+ Assert.assertTrue(NumberUtil.isInteger("256"));
+ Assert.assertTrue(NumberUtil.isInteger("0256"));
+ Assert.assertTrue(NumberUtil.isInteger("0"));
+ Assert.assertFalse(NumberUtil.isInteger("23.4"));
+ }
+
+ @Test
+ public void isLongTest() {
+ Assert.assertTrue(NumberUtil.isLong("-12"));
+ Assert.assertTrue(NumberUtil.isLong("256"));
+ Assert.assertTrue(NumberUtil.isLong("0256"));
+ Assert.assertTrue(NumberUtil.isLong("0"));
+ Assert.assertFalse(NumberUtil.isLong("23.4"));
+ }
+
+ @Test
+ public void isNumberTest() {
+ Assert.assertTrue(NumberUtil.isNumber("28.55"));
+ Assert.assertTrue(NumberUtil.isNumber("0"));
+ Assert.assertTrue(NumberUtil.isNumber("+100.10"));
+ Assert.assertTrue(NumberUtil.isNumber("-22.022"));
+ Assert.assertTrue(NumberUtil.isNumber("0X22"));
+ }
+
+ @Test
+ public void divTest() {
+ double result = NumberUtil.div(0, 1);
+ Assert.assertEquals(0.0, result, 0);
+ }
+
+ @Test
+ public void roundTest() {
+
+ // 四舍
+ String round1 = NumberUtil.roundStr(2.674, 2);
+ String round2 = NumberUtil.roundStr("2.674", 2);
+ Assert.assertEquals("2.67", round1);
+ Assert.assertEquals("2.67", round2);
+
+ // 五入
+ String round3 = NumberUtil.roundStr(2.675, 2);
+ String round4 = NumberUtil.roundStr("2.675", 2);
+ Assert.assertEquals("2.68", round3);
+ Assert.assertEquals("2.68", round4);
+
+ // 四舍六入五成双
+ String round31 = NumberUtil.roundStr(4.245, 2, RoundingMode.HALF_EVEN);
+ String round41 = NumberUtil.roundStr("4.2451", 2, RoundingMode.HALF_EVEN);
+ Assert.assertEquals("4.24", round31);
+ Assert.assertEquals("4.25", round41);
+
+ // 补0
+ String round5 = NumberUtil.roundStr(2.6005, 2);
+ String round6 = NumberUtil.roundStr("2.6005", 2);
+ Assert.assertEquals("2.60", round5);
+ Assert.assertEquals("2.60", round6);
+
+ // 补0
+ String round7 = NumberUtil.roundStr(2.600, 2);
+ String round8 = NumberUtil.roundStr("2.600", 2);
+ Assert.assertEquals("2.60", round7);
+ Assert.assertEquals("2.60", round8);
+ }
+
+ @Test
+ public void roundStrTest() {
+ String roundStr = NumberUtil.roundStr(2.647, 2);
+ Assert.assertEquals(roundStr, "2.65");
+ }
+
+ @Test
+ public void roundHalfEvenTest() {
+ String roundStr = NumberUtil.roundHalfEven(4.245, 2).toString();
+ Assert.assertEquals(roundStr, "4.24");
+ roundStr = NumberUtil.roundHalfEven(4.2450, 2).toString();
+ Assert.assertEquals(roundStr, "4.24");
+ roundStr = NumberUtil.roundHalfEven(4.2451, 2).toString();
+ Assert.assertEquals(roundStr, "4.25");
+ roundStr = NumberUtil.roundHalfEven(4.2250, 2).toString();
+ Assert.assertEquals(roundStr, "4.22");
+
+ roundStr = NumberUtil.roundHalfEven(1.2050, 2).toString();
+ Assert.assertEquals(roundStr, "1.20");
+ roundStr = NumberUtil.roundHalfEven(1.2150, 2).toString();
+ Assert.assertEquals(roundStr, "1.22");
+ roundStr = NumberUtil.roundHalfEven(1.2250, 2).toString();
+ Assert.assertEquals(roundStr, "1.22");
+ roundStr = NumberUtil.roundHalfEven(1.2350, 2).toString();
+ Assert.assertEquals(roundStr, "1.24");
+ roundStr = NumberUtil.roundHalfEven(1.2450, 2).toString();
+ Assert.assertEquals(roundStr, "1.24");
+ roundStr = NumberUtil.roundHalfEven(1.2550, 2).toString();
+ Assert.assertEquals(roundStr, "1.26");
+ roundStr = NumberUtil.roundHalfEven(1.2650, 2).toString();
+ Assert.assertEquals(roundStr, "1.26");
+ roundStr = NumberUtil.roundHalfEven(1.2750, 2).toString();
+ Assert.assertEquals(roundStr, "1.28");
+ roundStr = NumberUtil.roundHalfEven(1.2850, 2).toString();
+ Assert.assertEquals(roundStr, "1.28");
+ roundStr = NumberUtil.roundHalfEven(1.2950, 2).toString();
+ Assert.assertEquals(roundStr, "1.30");
+ }
+
+ @Test
+ public void decimalFormatTest() {
+ long c = 299792458;// 光速
+
+ String format = NumberUtil.decimalFormat(",###", c);
+ Assert.assertEquals("299,792,458", format);
+ }
+
+ @Test
+ public void decimalFormatMoneyTest() {
+ double c = 299792400.543534534;
+
+ String format = NumberUtil.decimalFormatMoney(c);
+ Assert.assertEquals("299,792,400.54", format);
+
+ double value = 0.5;
+ String money = NumberUtil.decimalFormatMoney(value);
+ Assert.assertEquals("0.50", money);
+ }
+
+ @Test
+ public void equalsTest() {
+ Assert.assertTrue(NumberUtil.equals(new BigDecimal("0.00"), BigDecimal.ZERO));
+ }
+
+ @Test
+ public void formatPercentTest() {
+ String str = NumberUtil.formatPercent(0.33543545, 2);
+ Assert.assertEquals("33.54%", str);
+ }
+
+ @Test
+ public void toBigDecimalTest() {
+ double a = 3.14;
+
+ BigDecimal bigDecimal = NumberUtil.toBigDecimal(a);
+ Assert.assertEquals("3.14", bigDecimal.toString());
+ }
+
+ @Test
+ public void maxTest() {
+ int max = NumberUtil.max(5,4,3,6,1);
+ Assert.assertEquals(6, max);
+ }
+
+ @Test
+ public void minTest() {
+ int min = NumberUtil.min(5,4,3,6,1);
+ Assert.assertEquals(1, min);
+ }
+
+ @Test
+ public void parseIntTest() {
+ int v1 = NumberUtil.parseInt("0xFF");
+ Assert.assertEquals(255, v1);
+ int v2 = NumberUtil.parseInt("010");
+ Assert.assertEquals(10, v2);
+ int v3 = NumberUtil.parseInt("10");
+ Assert.assertEquals(10, v3);
+ int v4 = NumberUtil.parseInt(" ");
+ Assert.assertEquals(0, v4);
+ int v5 = NumberUtil.parseInt("10F");
+ Assert.assertEquals(10, v5);
+ int v6 = NumberUtil.parseInt("22.4D");
+ Assert.assertEquals(22, v6);
+
+ int v7 = NumberUtil.parseInt("0");
+ Assert.assertEquals(0, v7);
+ }
+
+ @Test
+ public void parseLongTest() {
+ long v1 = NumberUtil.parseLong("0xFF");
+ Assert.assertEquals(255L, v1);
+ long v2 = NumberUtil.parseLong("010");
+ Assert.assertEquals(10L, v2);
+ long v3 = NumberUtil.parseLong("10");
+ Assert.assertEquals(10L, v3);
+ long v4 = NumberUtil.parseLong(" ");
+ Assert.assertEquals(0L, v4);
+ long v5 = NumberUtil.parseLong("10F");
+ Assert.assertEquals(10L, v5);
+ long v6 = NumberUtil.parseLong("22.4D");
+ Assert.assertEquals(22L, v6);
+ }
+
+ @Test
+ public void factorialTest(){
+ long factorial = NumberUtil.factorial(0);
+ Assert.assertEquals(1, factorial);
+
+ Assert.assertEquals(1L, NumberUtil.factorial(1));
+ Assert.assertEquals(1307674368000L, NumberUtil.factorial(15));
+ Assert.assertEquals(2432902008176640000L, NumberUtil.factorial(20));
+
+ factorial = NumberUtil.factorial(5, 0);
+ Assert.assertEquals(120, factorial);
+ factorial = NumberUtil.factorial(5, 1);
+ Assert.assertEquals(120, factorial);
+
+ Assert.assertEquals(5, NumberUtil.factorial(5, 4));
+ Assert.assertEquals(2432902008176640000L, NumberUtil.factorial(20, 0));
+ }
+
+ @Test
+ public void mulTest(){
+ final BigDecimal mul = NumberUtil.mul(new BigDecimal("10"), null);
+ Assert.assertEquals(BigDecimal.ZERO, mul);
+ }
+
+
+ @Test
+ public void isPowerOfTwoTest() {
+ Assert.assertEquals(false, NumberUtil.isPowerOfTwo(-1));
+ Assert.assertEquals(true, NumberUtil.isPowerOfTwo(16));
+ Assert.assertEquals(true, NumberUtil.isPowerOfTwo(65536));
+ Assert.assertEquals(true, NumberUtil.isPowerOfTwo(1));
+ Assert.assertEquals(false, NumberUtil.isPowerOfTwo(17));
+ }
+}