关于ip地址与网段(IP掩码形式)之间的校验

最近项目中需要校验某个ipv4是否在某个网段中，从网上找到了一些方法，下面做一下总结。

1.通过直接判断的方式，代码如下

public static boolean isInRange(String ip, String cidr) { String[] ips = ip.split("\\."); int ipAddr = (Integer.parseInt(ips[0]) << 24) | (Integer.parseInt(ips[1]) << 16) | (Integer.parseInt(ips[2]) << 8) | Integer.parseInt(ips[3]); int type = Integer.parseInt(cidr.replaceAll(".*/", "")); int mask = 0xFFFFFFFF << (32 - type); String cidrIp = cidr.replaceAll("/.*", ""); String[] cidrIps = cidrIp.split("\\."); int cidrIpAddr = (Integer.parseInt(cidrIps[0]) << 24) | (Integer.parseInt(cidrIps[1]) << 16) | (Integer.parseInt(cidrIps[2]) << 8) | Integer.parseInt(cidrIps[3]); return (ipAddr & mask) == (cidrIpAddr & mask); }

此方法使用示例：

public static void main(String[] args) { //掩码位支持1-32 System.out.println(isInRange("1.2.3.9","1.2.3.6/1")); System.out.println(isInRange("1.2.3.9","1.2.3.6/12")); System.out.println(isInRange("1.2.3.9","1.2.3.6/29")); System.out.println(isInRange("1.2.3.9","1.2.3.6/36")); }

2.可以先把网段转换成起始到结束ip，然后都转成数字，在判断是否在范围内，代码如下

/** * 根据网段计算开始IP * @param segment * @return 开始IP */ public static String getStartIp(String segment) { StringBuffer startIp = new StringBuffer(); if (segment == null) { return null; } String arr[] = segment.split("/"); String ip = arr[0]; String maskIndex = arr[1]; String mask = getNetMask(maskIndex); if (4 != ip.split("\\.").length || mask == null) { return null; } int ipArray[] = new int[4]; int netMaskArray[] = new int[4]; for (int i = 0; i < 4; i++) { try { ipArray[i] = Integer.parseInt(ip.split("\\.")[i]); netMaskArray[i] = Integer.parseInt(mask.split("\\.")[i]); if (ipArray[i] > 255 || ipArray[i] < 0 || netMaskArray[i] > 255 || netMaskArray[i] < 0) { return null; } ipArray[i] = ipArray[i] & netMaskArray[i]; if(i==3){ startIp.append(ipArray[i]+1); }else{ startIp.append(ipArray[i]+"."); } } catch (NumberFormatException e) { System.out.println(e.getMessage()); } } return startIp.toString(); } /** * 根据网段计算结束IP * @param segment * @return 结束IP */ public static String getEndIp(String segment) { StringBuffer endIp=new StringBuffer(); String startIp = getStartIp(segment); if (segment == null) { return null; } String arr[] = segment.split("/"); String maskIndex = arr[1]; //实际需要的IP个数 int hostNumber = 0; int startIpArray[] = new int[4]; try { hostNumber=1<<32-(Integer.parseInt(maskIndex)); for (int i = 0; i <4; i++) { startIpArray[i] = Integer.parseInt(startIp.split("\\.")[i]); if(i == 3){ startIpArray[i] = startIpArray[i] - 1; break; } } startIpArray[3] = startIpArray[3] + (hostNumber - 1); } catch (NumberFormatException e) { System.out.println(e.getMessage()); } if(startIpArray[3] >255){ int k = startIpArray[3] / 256; startIpArray[3] = startIpArray[3] % 256; startIpArray[2] = startIpArray[2] + k; } if(startIpArray[2] > 255){ int j = startIpArray[2] / 256; startIpArray[2] = startIpArray[2] % 256; startIpArray[1] = startIpArray[1] + j; if(startIpArray[1] > 255){ int k = startIpArray[1] / 256; startIpArray[1] = startIpArray[1] % 256; startIpArray[0] = startIpArray[0] + k; } } for(int i = 0; i < 4; i++){ if(i == 3){ startIpArray[i] = startIpArray[i] - 1; } if("" == endIp.toString()||endIp.length()==0){ endIp.append(startIpArray[i]); }else{ endIp.append("." + startIpArray[i]); } } return endIp.toString(); } /** * 根据掩码位数计算掩码 * @param maskIndex 掩码位 * @return 子网掩码 */ public static String getNetMask(String maskIndex) { StringBuilder mask = new StringBuilder(); Integer inetMask = 0; try { inetMask = Integer.parseInt(maskIndex); } catch (NumberFormatException e) { System.out.println(e.getMessage()); return null; } if (inetMask > 32) { return null; } // 子网掩码为1占了几个字节 int num1 = inetMask / 8; // 子网掩码的补位位数 int num2 = inetMask % 8; int array[] = new int[4]; for (int i = 0; i < num1; i++) { array[i] = 255; } for (int i = num1; i < 4; i++) { array[i] = 0; } for (int i = 0; i < num2; num2--) { array[num1] += 1 << 8 - num2; } for (int i = 0; i < 4; i++) { if (i == 3) { mask.append(array[i]); } else { mask.append(array[i] + "."); } } return mask.toString(); }

使用示例：

public static void main(String[] args) { System.out.println(getStartIp("1.2.3.6/12")); System.out.println(getEndIp("1.2.3.6/12")); }

ipv4地址转换成数字：

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