如何扫描所有IP地址范围？

Question

In MainActivity top I added array variable:

private final String[] ipaddresses = new String[]{
            "http://10.0.0.1:8098/?cmd=nothing",
            "http://10.0.0.3:8098/?cmd=nothing",
            "http://10.0.0.2:8098/?cmd=nothing"};

Then with a button click I use a for loop to iterate over each IP address . I check with a web server on my PC on which IP the PC is sitting. I send a command to the server and get back a result.

The question is, how I can build an array with all the logic available IP addresses? Since my PC can be sometimes on IP 10.0.0.2 and when I restart the pc or move to another PC the IP can be something else like 10.0.0.3

This is the button code where I also loop over the IPs

public void addListenerOnButton()
    {

        btnClick = (Button) findViewById(R.id.checkipbutton);

        btnClick.setOnClickListener(new OnClickListener()
        {
            byte[] response = null;
            @Override
            public void onClick(View arg0)
            {

                text = (TextView) findViewById(R.id.textView2);


                Thread t = new Thread(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        for (int i = 0; i < ipaddresses.length; i++)

                        {

                                try
                                {
                                    response = Get(ipaddresses[i]);
                                }
                                catch (Exception e)
                                {
                                    String err = e.toString();
                                }

                                if (response!=null)
                                {



                                    try
                                    {
                                        final String a = new String(response,"UTF-8");




                                        text.post(new Runnable()
                                        {
                                            @Override
                                            public void run()
                                            {
                                                text.setText(a);
                                            }
                                        });

                                        Logger.getLogger("MainActivity(inside thread)").info(a);
                                    } catch (UnsupportedEncodingException e)
                                    {
                                        e.printStackTrace();
                                        Logger.getLogger("MainActivity(inside thread)").info("encoding exception");
                                    }

                                    Logger.getLogger("MainActivity(inside thread)").info("test1");
                                    break;

                                }

                                else
                                {

                                }

                            text.post(new Runnable()
                            {
                                @Override
                                public void run()
                                {
                                    text.setText("Connection Failed");
                                }
                            });



                        }

                    }
                });
                t.start();
            }
        });

    }

New class:

package com.test.webservertest;

/**
 * Created by bout0 on 8/4/2015.
 */
public class IpAddresses
{
        private static String ipMain = "10.0.0.";
        private static int minIpRange = 0;
        private static int maxIpRange = 255;
        private static String[] ipAddresses = new String[maxIpRange];

        public static void main(String[] args) {
            for (int i = minIpRange; i < maxIpRange; i++) {
                String ipRange = ipMain + i;
                //IP range in Array
                //ipAddresses[i] = ipRange;

                //if you need full IP range in Url, then unmark the following 2 lines and mark above line
                String UrlRange = "http://" + ipRange + ":8098/?cmd=nothing";
                ipAddresses[i] = UrlRange;
            }

            //testing array results
            for (int i = minIpRange; i < maxIpRange; i++)
                System.out.println(ipAddresses[i]);
        }

}

Answer 1

Generating a set of IP Addresses from 10.0.0.0 to 10.0.0.255 is as simple as iterating through the list of valid digits for the last segment:

List<String> addresses = new ArrayList<>();
int min = 0;
int max = 255;
for(int i = min; i <= max; i++) {
    String address = "10.0.0." + i;
    addresses.add(address);
}

Now the addresses list has all of the valid IP addresses in it. What addresses are generated can be tweaked by adjusting the min and max values to shrink the available range of addresses.

Answer 2

Here is my suggestion:

public class IpRange {
    private static String ipMain = "10.0.0.";
    private static int minIpRange = 2;
    private static int maxIpRange = 255;
    private static String[] ipAddresses = new String[maxIpRange];

    public static void main(String[] args) {
        for (int i = minIpRange; i < maxIpRange; i++) {
            String ipRange = ipMain + i;
            //IP range in Array
            ipAddresses[i] = ipRange;

            //if you need full IP range in Url, then unmark the following 2 lines and mark above line
            //String urlRange = "http://" + ipRange + ":8098/?cmd=nothing";
            //ipAddresses[i] = urlRange;
        }

        //testing array results
        for (int i = minIpRange; i < maxIpRange; i++)
            System.out.println(ipAddresses[i]);
    }
}

IP addresses range in Array

10.0.0.2
10.0.0.3
10.0.0.4
10.0.0.5
etc.

Or the output will be like this as complete Url if required (just modify the code as noted):

http://10.0.0.2:8098/?cmd=nothing
http://10.0.0.3:8098/?cmd=nothing
http://10.0.0.4:8098/?cmd=nothing
http://10.0.0.5:8098/?cmd=nothing
http://10.0.0.6:8098/?cmd=nothing
etc.

Note: the class is made for demonstration and is just example how this task can be achieved, it is up the individual to modified it and implement it in the relative code, to fulfill the final requirement.

---

EDIT I have since optimized the code here is updated version:

public class IpRange {
    private String ipMain = "10.0.0.";
    private int startRange = 2; // 2 = 10.0.0.2
    private int endRange = 5;   // 5 = 10.0.0.5
    private int ipRangeLength = endRange - startRange;
    private String urlParam = ":8098/?cmd=nothing";

    public static void main(String[] args) {

        IpRange ipRange = new IpRange();

        // true -> ip range url with parameters / false -> only ip range
        String[] results = ipRange.ipRangeGenerator(true);

        for (String output : results)
            System.out.println(output);

    }

    public String[] ipRangeGenerator(boolean link) {
        String[] ipAddresses = new String[ipRangeLength];
        String urlRange;

        for (int i = 0; i < ipRangeLength; i++) {
            String ipRange = ipMain + (startRange + i);
            urlRange = ipRange;
            if (link)
                urlRange = "http://" + ipRange + urlParam;
            ipAddresses[i] = urlRange;
        }
        return ipAddresses;
    }

}