Messing with Class String. Error in the code that i can't figure out..

Question

There is an error in my code that i just can't seem to figure out. I've tried debbugin it but it seems to work when i do it by hand but when running it gives me the wrong value.... I will put part of the code and comment what i'm trying to do... Basically the whole idea of that part is to get an ip address from an input but for now i will consider putting in the IP Address. It should not exceed more than 4bytes so the max is 256.256.256.256
After that i have to seperate the "." from it and take each string seperately and see if it's greater than 256 than finally copy it into an array of bytes.... Here is the code..
//CODE//
NewIPAddress = ipText.getText();// Consider this for now as "10.1.1.127"
int x=0, y=0, i=0, z=0;
boolean error=false;
String IPString;
byte[] buffer = new byte[4];
int byteVal;
do
x=NewIPAddress.indexOf(".",z);
// This should get the first occurance
// in the third round it gives the
// wrong value i dont know why....
// If there is no occurance it returns
// -1
if(x!=-1)
IPString = NewIPAddress.substring(y,(x+z));
// I get the value one
// by one 10, 1, 1 ,127
byteVal=Integer.parseInt(IPString);
buffer=(byte)byteVal;
z=z+x;
y=z+1;
i++;
if(byteVal>256)
//If each value is greater than 256 then it's
//an error
JOptionPane.showMessageDialog(null,"Not a valid IP format","Error",JOptionPane.ERROR_MESSAGE);
break;
else
error=true;
while(!error);
//CODE//
If u have a better way of doing it or if u know why the third error is please let me know, i'll appreciate that...

Answer 1

Use a StringTokenizer (java.util.StringTokenizer) in stead, and specify '.' as the separator char:
import java.util.StringTokenizer;
public class Test
     public static void main( String[] args ) throws Exception
          byte[] bytes = createIpAddressArray( "10.1.1.127" );
          System.out.println( "Byte 1: " + bytes[0] );
          System.out.println( "Byte 2: " + bytes[1] );
          System.out.println( "Byte 3: " + bytes[2] );
          System.out.println( "Byte 4: " + bytes[3] );
     public static byte[] createIpAddressArray( String ipAddress ) throws Exception
          byte [] result = new byte[ 4 ];
          StringTokenizer ipTokens = new StringTokenizer( ipAddress, "." );
          int counter = 0;
          while( ipTokens.hasMoreTokens() )
               int ipPart = Integer.parseInt( ipTokens.nextToken() );
               if( ipPart < 265 && ipPart >= 0 )
                    result[ counter++ ] = ( byte ) ipPart;
               else
                    throw new Exception( "Bad IP address." );
          return result;