From bb29b97849ac6e50773e972a7618714bfd38a72e Mon Sep 17 00:00:00 2001
From: Zjp <1215582715@qq.com>
Date: Mon, 14 Nov 2022 20:23:55 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96NumberUtil.isPrime()=E6=96=B9?=
 =?UTF-8?q?=E6=B3=95:=201.=E4=BC=98=E5=8C=96=E6=89=A7=E8=A1=8C=E8=BF=87?=
 =?UTF-8?q?=E7=A8=8B,=20=E7=9B=B4=E6=8E=A5=E6=8E=92=E9=99=A4=E5=81=B6?=
 =?UTF-8?q?=E6=95=B0;=202.=E4=BF=AE=E6=94=B9=E5=87=BD=E6=95=B0=E5=90=8D,?=
 =?UTF-8?q?=20=E4=BB=8E=E5=A4=8D=E6=95=B0=E5=BD=A2=E5=BC=8F=E5=8F=98?=
 =?UTF-8?q?=E4=B8=BA=E5=8D=95=E6=95=B0;?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../main/java/cn/hutool/core/math/NumberUtil.java  | 11 +++++++++--
 .../java/cn/hutool/core/util/NumberUtilTest.java   | 14 ++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/hutool-core/src/main/java/cn/hutool/core/math/NumberUtil.java b/hutool-core/src/main/java/cn/hutool/core/math/NumberUtil.java
index 9d5152290..90cdf7c84 100644
--- a/hutool-core/src/main/java/cn/hutool/core/math/NumberUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/math/NumberUtil.java
@@ -805,9 +805,16 @@ public class NumberUtil {
 	 * @param n 数字
 	 * @return 是否是质数
 	 */
-	public static boolean isPrimes(final int n) {
+	public static boolean isPrime(final int n) {
 		Assert.isTrue(n > 1, "The number must be > 1");
-		for (int i = 2; i <= Math.sqrt(n); i++) {
+		if (n <= 3) {
+			return true;
+		} else if ((n & 1) == 0) {
+			// 快速排除偶数
+			return false;
+		}
+		final int end = (int) Math.sqrt(n);
+		for (int i = 3; i <= end; i += 2) {
 			if (n % i == 0) {
 				return false;
 			}
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 0089c0481..69e67d368 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
@@ -459,4 +459,18 @@ public class NumberUtilTest {
 		//noinspection ResultOfMethodCallIgnored
 		NumberUtil.range(0, Integer.MIN_VALUE);
 	}
+
+	@Test
+	public void isPrimeTest(){
+		Assert.assertTrue(NumberUtil.isPrime(2));
+		Assert.assertTrue(NumberUtil.isPrime(3));
+		Assert.assertTrue(NumberUtil.isPrime(7));
+		Assert.assertTrue(NumberUtil.isPrime(17));
+		Assert.assertTrue(NumberUtil.isPrime(296731));
+		Assert.assertTrue(NumberUtil.isPrime(99999989));
+
+		Assert.assertFalse(NumberUtil.isPrime(4));
+		Assert.assertFalse(NumberUtil.isPrime(296733));
+		Assert.assertFalse(NumberUtil.isPrime(20_4123_2399));
+	}
 }