www.pudn.com > network-java.rar > HostAccount.java

package netManager.discovery; 
 
/** 
 * 
Title: HostAccount 
 
 * 
Description: 估算子网内可能存在的最多主机 
 
 * 
Copyright: Copyright (c) 2006 
 
 * 
Company: 
 
 * @author：谢飞 
 * @version 1.0 
 */ 
  
import java.net.InetAddress; 
import org.apache.commons.logging.Log; 
import org.apache.commons.logging.LogFactory; 
import netManager.framework.exception.BaseException;	 
  
public class HostAccount{ 
	 
	private String subnetMask; 
	private Log log = LogFactory.getLog("HostAccount"); 
 	 
 	public HostAccount() throws BaseException{ 
 		subnetMask = SubnetMask.getSubnetMask(); 
 	} 
 	 
 	/** 
 	 *根据子网掩码求得当前子网内最多可能主机数 
 	 */ 
 	public int getMaxHosts(){ 
 		int maxHosts = 1; 
 		try{ 
 			String binaryIP = Convert.toBinary(subnetMask);	//将IP地址从十进制转换为二进制形式 
 			int position = binaryIP.indexOf("0"); 
 			String calPart = binaryIP.substring(position);	 
 			for(int i=1;i<=calPart.length();i++){ 
 				maxHosts = maxHosts * 2; 
 			} 
 			double d = (maxHosts/255);										 
 			int i = new Double(d).intValue(); 
 			maxHosts = maxHosts - ( 2 * i);					//IP地址中末尾为0或255的为特殊用途，不计在Hosts中 
 			//System.out.println("子网内最多主机数为: " + hosts);	 
 		} 
 		catch(Exception e){ 
 			e.printStackTrace(); 
 			log.error(e); 
 		} 
 		return maxHosts; 
 	} 
 	 
}