常用正则表达式-IP地址

1. IPv4地址

1. IPv4地址定义

参考百度百科

IPv4使用32位（4字节）地址，因此地址空间中只有4,294,967,296（即2的32次方）个地址。

通常使用点分十进制进行表示方法，如0.0.0.0-255.255.255.255。

2. IPv4地址的正则表达式

一个合法的IPv4地址由4组数字组成，每组数字之间以.隔开，数字的取值范围为0-255。每组数字的总结如下：

所以每组数字的正则表达式为：

(\d)|([1-9]\d)|(1\d{2})|(2[0-4]\d)|(25[0-5])

注：每种情况务必加上()，因为元字符|对邻接的字符/字符集/子表达式都起作用。

进而，IPv4的完整正则表达式为:

(((\d)|([1-9]\d)|(1\d{2})|(2[0-4]\d)|(25[0-5]))\.){3}((\d)|([1-9]\d)|(1\d{2})|(2[0-4]\d)|(25[0-5]))

对应java代码的正则为：

String IP_V4 = "^(((\\d)|([1-9]\\d)|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))\\.){3}((\\d)|([1-9]\\d)|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))$"

3. 对应java代码

IPValidator.java

package com.ysx.utils.pattern;import java.util.regex.Pattern;/*** @author youngbear* @email youngbear@* @date -09-04 17:54* @blog <a href="/next_second">...</a>* @github <a href="/YoungBear">...</a>* @description IP校验*/public class IPValidator {private static final String IP_V4 = "^(((\\d)|([1-9]\\d)|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))\\.){3}((\\d)|([1-9]\\d)|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))$";// 下边这个正则也ok// private static final String IP_V4 = "^(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}$";private static final Pattern IP_V4_PATTERN = pile(IP_V4);/*** 是否是有效的ipv4地址** @param input 字符串* @return 是否是有效的ipv4地址*/public static boolean isValidIpv4(String input) {if (input == null) {return false;}return IP_V4_PATTERN.matcher(input).matches();}}

使用junit5单元测试：IPValidatorTest.java

package com.ysx.utils.pattern;import org.junit.jupiter.params.ParameterizedTest;import org.junit.jupiter.params.provider.MethodSource;import java.util.stream.Stream;import static org.junit.jupiter.api.Assertions.assertFalse;import static org.junit.jupiter.api.Assertions.assertTrue;/*** @author youngbear* @email youngbear@* @date -09-04 17:58* @blog <a href="/next_second">...</a>* @github <a href="/YoungBear">...</a>* @description*/public class IPValidatorTest {@ParameterizedTest(name = "#{index} - Run test with IPv4 = {0}")@MethodSource("validIPv4Provider")void test_ipv4_regex_valid(String ipv4) {assertTrue(IPValidator.isValidIpv4(ipv4));}@ParameterizedTest(name = "#{index} - Run test with IPv4 = {0}")@MethodSource("invalidIPv4Provider")void test_ipv4_regex_invalid(String ipv4) {assertFalse(IPValidator.isValidIpv4(ipv4));}static Stream<String> validIPv4Provider() {return Stream.of("0.0.0.0","0.0.0.1","127.0.0.1","1.2.3.4", // 0-9"11.1.1.0", // 10-99"101.1.1.0", // 100-199"201.1.1.0", // 200-249"255.255.255.255",// 250-255"192.168.1.1","192.168.1.255","100.100.100.100");}static Stream<String> invalidIPv4Provider() {return Stream.of("000.000.000.000",// leading 0"00.00.00.00", // leading 0"1.2.3.04", // leading 0"1.02.03.4",// leading 0"1.2", // 1 dot"1.2.3",// 2 dots"1.2.3.4.5",// 4 dots"192.168.1.1.1", // 4 dots"256.1.1.1",// 256"1.256.1.1",// 256"1.1.256.1",// 256"1.1.1.256",// 256"-100.1.1.1",// -100"1.-100.1.1",// -100"1.1.-100.1",// -100"1.1.1.-100",// -100"1...1",// empty between ."1..1", // empty between ."1.1.1.1.", // last .""); // empty}}

源代码地址

参考

1. Java IP Address (IPv4) regex examples

其他的ipv4地址的正则及问题

有问题的

// /post/6844903768232820749// 有问题 00.00.00.00 认为是有效的String IP_V4 = "^(((\\d{1,2})|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))\\.){3}((\\d{1,2})|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))$";// /example/java/java.util.regex/is-ipv4-address-by-regex.html// -- 有问题 000.000.000.000 认为是合法的String IPV4_PATTERN ="^(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)(\\.(25[0-5]|2[0-4]\\d|[0-1]?\\d?\\d)){3}$"// /regular-expressions/how-to-validate-ip-address-with-regular-expression/String IPV4_PATTERN ="^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\\.(?!$)|$)){4}$"

正确的：

// /regular-expressions/how-to-validate-ip-address-with-regular-expression/ // 25[0-5] = 250-255// (2[0-4])[0-9] = 200-249// (1[0-9])[0-9] = 100-199// ([1-9])[0-9] = 10-99// [0-9]= 0-9// (\.(?!$))= can't end with a dotprivate static final String IPV4_PATTERN_SHORTEST ="^((25[0-5]|(2[0-4]|1[0-9]|[1-9]|)[0-9])(\\.(?!$)|$)){4}$";