在项目中经常会用到IP（v4）范围判定比较的功能，一般将IP转化为整数再进行比较。
一、基本知识点
IP ——> 整数：
- 把IP地址转化为字节数组
- 通过左移位（<<）、与（&）、或（|）这些操作转为int
整数 ——> IP：
- 将整数值进行右移位操作（>>>），右移24位，再进行与操作符（&）0xFF，得到的数字即为第一段IP。
- 将整数值进行右移位操作（>>>），右移16位，再进行与操作符（&）0xFF，得到的数字即为第二段IP。
- 将整数值进行右移位操作（>>>），右移8位，再进行与操作符（&）0xFF，得到的数字即为第三段IP。
- 将整数值进行与操作符（&）0xFF，得到的数字即为第四段IP。
二、java代码示例
IPv4Util.java
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package michael.utils; import java.net.InetAddress; /** * @author michael <br> * blog: http://www.micmiu.com <br> * mail: sjsky007@gmail.com */ public class IPv4Util { private final static int INADDRSZ = 4; /** * 把IP地址转化为字节数组 * @param ipAddr * @return byte[] */ public static byte[] ipToBytesByInet(String ipAddr) { try { return InetAddress.getByName(ipAddr).getAddress(); } catch (Exception e) { throw new IllegalArgumentException(ipAddr + " is invalid IP"); } } /** * 把IP地址转化为int * @param ipAddr * @return int */ public static byte[] ipToBytesByReg(String ipAddr) { byte[] ret = new byte[4]; try { String[] ipArr = ipAddr.split("\\."); ret[0] = (byte) (Integer.parseInt(ipArr[0]) & 0xFF); ret[1] = (byte) (Integer.parseInt(ipArr[1]) & 0xFF); ret[2] = (byte) (Integer.parseInt(ipArr[2]) & 0xFF); ret[3] = (byte) (Integer.parseInt(ipArr[3]) & 0xFF); return ret; } catch (Exception e) { throw new IllegalArgumentException(ipAddr + " is invalid IP"); } } /** * 字节数组转化为IP * @param bytes * @return int */ public static String bytesToIp(byte[] bytes) { return new StringBuffer().append(bytes[0] & 0xFF).append('.').append( bytes[1] & 0xFF).append('.').append(bytes[2] & 0xFF) .append('.').append(bytes[3] & 0xFF).toString(); } /** * 根据位运算把 byte[] -> int * @param bytes * @return int */ public static int bytesToInt(byte[] bytes) { int addr = bytes[3] & 0xFF; addr |= ((bytes[2] << 8 ) & 0xFF00); addr |= ((bytes[1] << 16) & 0xFF0000); addr |= ((bytes[0] << 24) & 0xFF000000); return addr; } /** * 把IP地址转化为int * @param ipAddr * @return int */ public static int ipToInt(String ipAddr) { try { return bytesToInt(ipToBytesByInet(ipAddr)); } catch (Exception e) { throw new IllegalArgumentException(ipAddr + " is invalid IP"); } } /** * ipInt -> byte[] * @param ipInt * @return byte[] */ public static byte[] intToBytes(int ipInt) { byte[] ipAddr = new byte[INADDRSZ]; ipAddr[0] = (byte) ((ipInt >>> 24) & 0xFF); ipAddr[1] = (byte) ((ipInt >>> 16) & 0xFF); ipAddr[2] = (byte) ((ipInt >>> 8 ) & 0xFF); ipAddr[3] = (byte) (ipInt & 0xFF); return ipAddr; } /** * 把int->ip地址 * @param ipInt * @return String */ public static String intToIp(int ipInt) { return new StringBuilder().append(((ipInt >> 24) & 0xff)).append('.') .append((ipInt >> 16) & 0xff).append('.').append( (ipInt >> 8 ) & 0xff).append('.').append((ipInt & 0xff)) .toString(); } /** * 把192.168.1.1/24 转化为int数组范围 * @param ipAndMask * @return int[] */ public static int[] getIPIntScope(String ipAndMask) { String[] ipArr = ipAndMask.split("/"); if (ipArr.length != 2) { throw new IllegalArgumentException("invalid ipAndMask with: " + ipAndMask); } int netMask = Integer.valueOf(ipArr[1].trim()); if (netMask < 0 || netMask > 31) { throw new IllegalArgumentException("invalid ipAndMask with: " + ipAndMask); } int ipInt = IPv4Util.ipToInt(ipArr[0]); int netIP = ipInt & (0xFFFFFFFF << (32 - netMask)); int hostScope = (0xFFFFFFFF >>> netMask); return new int[] { netIP, netIP + hostScope }; } /** * 把192.168.1.1/24 转化为IP数组范围 * @param ipAndMask * @return String[] */ public static String[] getIPAddrScope(String ipAndMask) { int[] ipIntArr = IPv4Util.getIPIntScope(ipAndMask); return new String[] { IPv4Util.intToIp(ipIntArr[0]), IPv4Util.intToIp(ipIntArr[1]) }; } /** * 根据IP 子网掩码（192.168.1.1 255.255.255.0）转化为IP段 * @param ipAddr ipAddr * @param mask mask * @return int[] */ public static int[] getIPIntScope(String ipAddr, String mask) { int ipInt; int netMaskInt = 0, ipcount = 0; try { ipInt = IPv4Util.ipToInt(ipAddr); if (null == mask || "".equals(mask)) { return new int[] { ipInt, ipInt }; } netMaskInt = IPv4Util.ipToInt(mask); ipcount = IPv4Util.ipToInt("255.255.255.255") - netMaskInt; int netIP = ipInt & netMaskInt; int hostScope = netIP + ipcount; return new int[] { netIP, hostScope }; } catch (Exception e) { throw new IllegalArgumentException("invalid ip scope express ip:" + ipAddr + " mask:" + mask); } } /** * 根据IP 子网掩码（192.168.1.1 255.255.255.0）转化为IP段 * @param ipAddr ipAddr * @param mask mask * @return String[] */ public static String[] getIPStrScope(String ipAddr, String mask) { int[] ipIntArr = IPv4Util.getIPIntScope(ipAddr, mask); return new String[] { IPv4Util.intToIp(ipIntArr[0]), IPv4Util.intToIp(ipIntArr[0]) }; } /** * @param args * @throws Exception */ public static void main(String[] args) throws Exception { String ipAddr = "192.168.8.1"; byte[] bytearr = IPv4Util.ipToBytesByInet(ipAddr); StringBuffer byteStr = new StringBuffer(); for (byte b : bytearr) { if (byteStr.length() == 0) { byteStr.append(b); } else { byteStr.append("," + b); } } System.out.println("IP: " + ipAddr + " ByInet --> byte[]: [ " + byteStr + " ]"); bytearr = IPv4Util.ipToBytesByReg(ipAddr); byteStr = new StringBuffer(); for (byte b : bytearr) { if (byteStr.length() == 0) { byteStr.append(b); } else { byteStr.append("," + b); } } System.out.println("IP: " + ipAddr + " ByReg --> byte[]: [ " + byteStr + " ]"); System.out.println("byte[]: " + byteStr + " --> IP: " + IPv4Util.bytesToIp(bytearr)); int ipInt = IPv4Util.ipToInt(ipAddr); System.out.println("IP: " + ipAddr + " --> int: " + ipInt); System.out.println("int: " + ipInt + " --> IP: " + IPv4Util.intToIp(ipInt)); String ipAndMask = "192.168.1.1/24"; int[] ipscope = IPv4Util.getIPIntScope(ipAndMask); System.out.println(ipAndMask + " --> int地址段：[ " + ipscope[0] + "," + ipscope[1] + " ]"); System.out.println(ipAndMask + " --> IP 地址段：[ " + IPv4Util.intToIp(ipscope[0]) + "," + IPv4Util.intToIp(ipscope[1]) + " ]"); String ipAddr1 = "192.168.1.1", ipMask1 = "255.255.255.0"; int[] ipscope1 = IPv4Util.getIPIntScope(ipAddr1, ipMask1); System.out.println(ipAddr1 + " , " + ipMask1 + " --> int地址段 ：[ " + ipscope1[0] + "," + ipscope1[1] + " ]"); System.out.println(ipAddr1 + " , " + ipMask1 + " --> IP地址段 ：[ " + IPv4Util.intToIp(ipscope1[0]) + "," + IPv4Util.intToIp(ipscope1[1]) + " ]"); } } |
测试运行结果：
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IP: 192.168.8.1 ByInet --> byte[]: [ -64,-88,8,1 ] IP: 192.168.8.1 ByReg --> byte[]: [ -64,-88,8,1 ] byte[]: -64,-88,8,1 --> IP: 192.168.8.1 IP: 192.168.8.1 --> int: -1062729727 int: -1062729727 --> IP: 192.168.8.1 192.168.1.1/24 --> int地址段：[ -1062731520,-1062731265 ] 192.168.1.1/24 --> IP 地址段：[ 192.168.1.0,192.168.1.255 ] 192.168.1.1 , 255.255.255.0 --> int地址段 ：[ -1062731520,-1062731265 ] 192.168.1.1 , 255.255.255.0 --> IP地址段 ：[ 192.168.1.0,192.168.1.255 ] |
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ava中使用substance look&feel加水印，水印总是显示不出来
请问你用过sub么？
sorry,substance 我没有怎么接触过的，没办法给你提出建议的