本文實例講述了JAVA中IP和整數相互轉化的方法。分享給大家供大家參考。具體分析如下：
一、基本知識點
IP ――> 整數：
把IP地址轉化為字節數組通過左移位（<<）、與（&）、或（|）這些操作轉為int
整數――> IP：
將整數值進行右移位操作（>>>），右移24位，再進行與操作符（&）0xFF，得到的數字即為第一段IP。
將整數值進行右移位操作（>>>），右移16位，再進行與操作符（&）0xFF，得到的數字即為第二段IP。
將整數值進行右移位操作（>>>），右移8位，再進行與操作符（&）0xFF，得到的數字即為第三段IP。
將整數值進行與操作符（&）0xFF，得到的數字即為第四段IP。
二、java代碼示例（IPv4Util.java）
package michael.utils; import java.net.InetAddress; public class IPv4Util { private final static int INADDRSZ = 4; public static byte[] ipToBytesByInet(String ipAddr) { try { return InetAddress.getByName(ipAddr).getAddress(); } catch (Exception e) { throw new IllegalArgumentException(ipAddr + " is invalid IP"); } }JTA實踐:Spring+ATOMIKOS 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"); } } 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(); } 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; } public static int ipToInt(String ipAddr) { try { return bytesToInt(ipToBytesByInet(ipAddr)); } catch (Exception e) { throw new IllegalArgumentException(ipAddr + " is invalid IP"); } } 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; } 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(); } 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 }; } public static String[] getIPAddrScope(String ipAndMask) { int[] ipIntArr = IPv4Util.getIPIntScope(ipAndMask); return new String[] { IPv4Util.intToIp( ipIntArr[0]), IPv4Util.intToIp(ipIntArr[0]) }; } 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); } } 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]) }; } 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]) + " ]"); } }希望本文所述對大家的java程序設計有所幫助。