ipversion.java

这是一张java应用教程的随书光盘

import java.net.*;
import java.io.*;
public class IPVersion 
{public static void main(String args[])
	{try
 		{InetAddress inetadd=InetAddress.getLocalHost();
  		 byte[ ] address=inetadd.getAddress( );
         if(address.length==4)	
           {System.out.println("The ip version is ipv4");
            int firstbyte=address[0];
            if (firstbyte<0)
              firstbyte += 256;
            if((firstbyte&0x80)==0 )
           	  System.out.println("the ip class is A");
            else if ((firstbyte&0xC0)==0x80 )
             System.out.println("The ip class is B");
            else if((firstbyte&0xE0)==0xC0 ) 
             System.out.println("The ip class is C");
            else if((firstbyte&0xF0)==0xE0)
             System.out.println("The ip class is D");
            else if((firstbyte&0xF8)==0xF0 )
             System.out.println("The ip class is E");				
           }
         else if(address.length==16)
           System.out.println("The ip version is ipv6");
        }
    catch (Exception e){ };
  }
}