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Merge pull request #1132 from akiyamaneko/patch-4

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NumberUtil 增加新功能 isPowerOfTwo 判断整数是否是2的幂
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Golden Looly 2020-09-28 15:04:09 +08:00 committed by GitHub
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11
hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java
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@ -2157,6 +2157,17 @@ public class NumberUtil {
return number.pow(n); return number.pow(n);
} }
/**
* 判断一个整数是否是2的幂
*
* @param n 待验证的整数
* @return 如果n是2的幂返回true, 反之返回false
*/
public static boolean isPowerOfTwo(long n) {
return (n > 0) && ((n & (n - 1)) == 0);
}
/** /**
* 解析转换数字字符串为int型数字，规则如下： * 解析转换数字字符串为int型数字，规则如下：
* *

10
hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java
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@ -254,4 +254,14 @@ public class NumberUtilTest {
final BigDecimal mul = NumberUtil.mul(new BigDecimal("10"), null); final BigDecimal mul = NumberUtil.mul(new BigDecimal("10"), null);
Assert.assertEquals(BigDecimal.ZERO, mul); 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));
}
} }