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Thread: wanting 2nd octet of an IP address

  1. #1
    Junior Member
    Join Date
    Jul 2012
    Thanked 0 Times in 0 Posts

    Default wanting 2nd octet of an IP address

    I don't know enough java, so I am probably doing this wrong. What I would like to have, is a String that has the second octet of an IP address, weather it is an 8 or 58 or 103, just as an example.

    import java.net.*;
    import java.io.*;
    import javax.swing.JOptionPane;
    public class findip {
    public static void main(String [] args) throws IOException{
    	String myip,myip2;
    	InetAddress thisIp =InetAddress.getLocalHost();
    	//System.out.println("IP of my system is := "+thisIp.getHostAddress());
    	//need to just show or have 2nd octet
    	JOptionPane.showMessageDialog(null,"IP:__"+myip+"\n\nSchool Num:__"+myip2);

  2. #2
    Join Date
    Jul 2012
    Thanked 19 Times in 19 Posts

    Default Re: wanting 2nd octet of an IP address

    It's not an octet. It's decimal. This example here shows the last part of an IP. You can modify it to get the 1st, 2nd or 3rd part.
    1st: myIP.substring(0, myIP.indexOf(".");
    2nd: myIP.substring(myIP.indexOf(".")+1, myIP.indexOf(".", myIP.indexOf(".")+1));
    import javax.swing.JOptionPane;
    import java.net.InetAddress;
    public class WhatIP {
    	public static void main(String[] args) {
    		try {
    			InetAddress ia = InetAddress.getByName(args[0]);
    			String myIP = ia.toString();
    			JOptionPane.showMessageDialog( null, myIP+"last Part = "+myIP.substring(myIP.lastIndexOf('.')+q, myIP.length())); 
    		} catch (Exception e) {

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