如何用java获得子网掩码?
大家好!   
 如何用java获得子网掩码?包括linux和windows下的,有什么类可用? 
 最好给出些代码,谢谢!!
------解决方案--------------------20?? 现在的知识,越来越不值钱了     
 public static void main(String[] args) { 
 		try { 
 			Enumeration <NetworkInterface>  eni = NetworkInterface.getNetworkInterfaces(); 
 			while (eni.hasMoreElements()) { 
 				NetworkInterface ni = eni.nextElement(); 
 				List <InterfaceAddress>  lia = ni.getInterfaceAddresses(); 
 				Iterator <InterfaceAddress>  iia = lia.iterator(); 
 				while (iia.hasNext()) { 
 					InterfaceAddress ia = iia.next(); 
 					InetAddress a = ia.getAddress(); 
 					if (!a.isLoopbackAddress()) { 
 						String ha = a.getHostAddress(); 
 						System.out.println( "address =  " + ha); 
 						short ml = (short) (ia.getNetworkPrefixLength() / 8); 
 						String[] as = ha.split( "\\. "); 
 						String ns =  " "; 
 						for (int i = 0; i  < ml; i++) { 
 							ns += as[i]; 
 							if (i  < ml - 1) { 
 								ns +=  ". "; 
 							} 
 						} 
 						System.out.println( "subnet =  " + ns); 
 					} 
 				}  				 
 			} 
 		} catch (Exception e) { 
 			e.printStackTrace(); 
 		}  		 
 	}