Java：判断IP4地址合法性

Java：判断IP4地址合法性

一、判断IP4地址是否是合法地址

         1. 最容易理解的方式

public static boolean validIP(String ip) {try {if (ip == null || ip.isEmpty()) {return false;}String[] parts = ip.split("\\.");if (parts.length != 4) {return false;}for (String s : parts) {int i = Integer.parseInt(s);if ((i < 0) || (i > 255)) {return false;}}if (ip.endsWith(".")) {return false;}return true;} catch (NumberFormatException nfe) {return false;}}

         2. 正则表达式判断

public static boolean validIP(String ip) {if (ip == null || ip.isEmpty())return false;ip = ip.trim();if ((ip.length() < 6) & (ip.length() > 15))return false;try {String rule = "^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.)" +   "{3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$";Pattern pattern = Pattern.compile(rule);Matcher matcher = pattern.matcher(ip);return matcher.matches();} catch (PatternSyntaxException ex) {return false;}}

         3. 使用commons-validator中的方法判断

public static boolean validIP(String ip) {return InetAddressValidator.getInstance().isValidInet4Address(ip);}

二、IP与整数之间相互转换

1. IP地址转换成整数

方法1：

public static long ip2long(String ip) {String[] ipArray = ip.split("\\.");long result = 0;for (int i = 0; i < ipArray.length; i++) {int power = 3 - i;result += (Integer.parseInt(ipArray[i]) % 256 * Math.pow(256, power));}return result;}

方法2：

public static long ip2long(String ip) {long result = 0;String[] ipAddressInArray = ip.split("\\.");for (int i = 3; i >= 0; i--) {long temp = Long.parseLong(ipAddressInArray[3 - i]);result |= temp << (i * 8);}return result;}

2. 整数转换成IP地址

方法1：

public static String long2ip(long decimal) {StringBuffer result = new StringBuffer(15);for (int i = 0; i < 4; i++) {result.insert(0,Long.toString(decimal & 0xff));if (i < 3) {result.insert(0,'.');}decimal = decimal >> 8;}return result.toString();}

方法2：

public static String long2ip(long decimal) {return ((decimal >> 24) & 0xFF) + "." +    ((decimal >> 16) & 0xFF) + "." +    ((decimal >> 8 ) & 0xFF) + "." +    (decimal & 0xFF);}

三、判断IP地址是否在某个地址段内

public static boolean isRange(String ip, String start, String end){long temp = ip2long(ip);long low = ip2long(start);long high = ip2long(end);return temp >= low && temp <= high;}