I want the fastest way to search all Ip addresses of the PC's connected to Lan using JAVA and placed all it in JCOMBOBOX?

Question

I want the fastest way to find all the IP addresses of the PCs connected to the Lan

for(i=0;i<255;i++)

This kind of the code takes too much for searching and displaying . I want display ip addresses in the combobox. It takes 8 minutes to run and find ip addresses connected to the Lan.

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package backupdropbox;

import java.io.IOException; import java.net.InetAddress; import java.net.Socket; import java.net.UnknownHostException; import java.util.logging.Level; import java.util.logging.Logger;

/** * * @author Administrator */ public class Threading {

static InetAddress address;
static InetAddress localhost;
static Runnable r2 = new Runnable() {

    public void run() {



        try {
            localhost = InetAddress.getLocalHost();
        } catch (UnknownHostException ex) {
            Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
        }
        // this code assumes IPv4 is used
        byte[] ip = localhost.getAddress();
        for (int i = 1; i <= 50; i++) {
            ip[3] = (byte) i;
            try {
                address = InetAddress.getByAddress(ip);
            } catch (UnknownHostException ex) {
                Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
            }
            //   System.out.println("address"+address);
            String ip1 = address.getHostAddress();
            try {
                if (address.isReachable(2000)) {
                    try {
                        Socket ServerSok = new Socket(ip1, 3260);
                        System.out.println("Port in use: " + address);
                        ServerSok.close();
                    } catch (Exception e) {
                    }
                }
            } catch (IOException ex) {
                Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
            }

        }




    }
};
static Runnable r1 = new Runnable() {

    public void run() {



        try {
            localhost = InetAddress.getLocalHost();
        } catch (UnknownHostException ex) {
            Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
        }
        // this code assumes IPv4 is used
        byte[] ip = localhost.getAddress();
        for (int i = 51; i <= 100; i++) {
            ip[3] = (byte) i;
            try {
                address = InetAddress.getByAddress(ip);
            } catch (UnknownHostException ex) {
                Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
            }
            //   System.out.println("address"+address);
            String ip1 = address.getHostAddress();
            try {
                if (address.isReachable(2000)) {
                    try {
                        Socket ServerSok = new Socket(ip1, 3260);
                        System.out.println("Port in use: " + address);
                        ServerSok.close();
                    } catch (Exception e) {
                    }
                }
            } catch (IOException ex) {
                Logger.getLogger(Threading.class.getName()).log(Level.SEVERE, null, ex);
            }

        }




    }
};





public static void main(String args[]) {

    Thread thr1 = new Thread(r1);
    Thread thr2 = new Thread(r2);


    thr1.start();
    thr2.start();


}

}

here is my code after creating threads

You cannot magically find IP addresses. Consult your network admin. — SLaks, May 20 '11 at 11:17
Use threads to break up your workload instead of examining the IP addresses serially. — Jonathon Faust, May 20 '11 at 11:18
http://stackoverflow.com/questions/3345857/how-to-get-list-of-ip-connected-in-lan-using-java — jmj, May 20 '11 at 11:26
thanks for giving link but this link has the same issue it takes too much time for searching and displaying,i had break the thread but it gives different ip addresses each time when the code get runs — Nilesh410451, May 23 '11 at 10:35

score 2 · Answer 1 · answered May 20 '11 at 11:19

2

It sounds like you already have code that checks whether the given IP address is live.

Now, instead of running the code in a loop, you could either make it asynchronous, or partition the list of IP addresses to be checked across multiple threads.

answered May 20 '11 at 11:19

NPE

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i have partitioned it but i gives the different ip addresses each time \ – Nilesh410451 May 23 '11 at 10:26
i have added code in the question section – Nilesh410451 May 23 '11 at 10:27

score 0 · Answer 2 · answered May 20 '11 at 11:33

0

@Nilesh410451 I would be interested in seeing your code which does that. It might be useful one day.

As to a solution for your problem the answer is threading. You might use a SwingWorker to work in the background finding the new IPs then using invokeLater method from SwingUtilitis update the user GUI. Here you have not bad tutorial considering this type of issue.

answered May 20 '11 at 11:33

Boro

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thanks but it will take the same time even used in the swingworker – Nilesh410451 May 23 '11 at 10:20
i have added the code in the above question – Nilesh410451 May 23 '11 at 10:21

I want the fastest way to search all Ip addresses of the PC's connected to Lan using JAVA and placed all it in JCOMBOBOX?

2 Answers2