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echo.javaAPI DocApache Commons NET 1.4.1 API5210Sat Dec 03 10:05:48 GMT 2005examples

echo

public final class echo extends Object
This is an example program demonstrating how to use the EchoTCPClient and EchoUDPClient classes. This program connects to the default echo service port of a specified server, then reads lines from standard input, writing them to the echo server, and then printing the echo. The default is to use the TCP port. Use the -udp flag to use the UDP port.

Usage: echo [-udp]

Fields Summary
Constructors Summary
Methods Summary
public static final voidechoTCP(java.lang.String host)

        EchoTCPClient client = new EchoTCPClient();
        BufferedReader input, echoInput;
        PrintWriter echoOutput;
        String line;

        // We want to timeout if a response takes longer than 60 seconds
        client.setDefaultTimeout(60000);
        client.connect(host);
        System.out.println("Connected to " + host + ".");
        input = new BufferedReader(new InputStreamReader(System.in));
        echoOutput =
            new PrintWriter(new OutputStreamWriter(client.getOutputStream()), true);
        echoInput =
            new BufferedReader(new InputStreamReader(client.getInputStream()));

        while ((line = input.readLine()) != null)
        {
            echoOutput.println(line);
            System.out.println(echoInput.readLine());
        }

        client.disconnect();
public static final voidechoUDP(java.lang.String host)

        int length, count;
        byte[] data;
        String line;
        BufferedReader input;
        InetAddress address;
        EchoUDPClient client;

        input = new BufferedReader(new InputStreamReader(System.in));
        address = InetAddress.getByName(host);
        client = new EchoUDPClient();

        client.open();
        // If we don't receive an echo within 5 seconds, assume the packet is lost.
        client.setSoTimeout(5000);
        System.out.println("Ready to echo to " + host + ".");

        // Remember, there are no guarantees about the ordering of returned
        // UDP packets, so there is a chance the output may be jumbled.
        while ((line = input.readLine()) != null)
        {
            data = line.getBytes();
            client.send(data, address);
            count = 0;
            do
            {
                try
                {
                    length = client.receive(data);
                }
                // Here we catch both SocketException and InterruptedIOException,
                // because even though the JDK 1.1 docs claim that
                // InterruptedIOException is thrown on a timeout, it seems
                // SocketException is also thrown.
                catch (SocketException e)
                {
                    // We timed out and assume the packet is lost.
                    System.err.println(
                        "SocketException: Timed out and dropped packet");
                    break;
                }
                catch (InterruptedIOException e)
                {
                    // We timed out and assume the packet is lost.
                    System.err.println(
                        "InterruptedIOException: Timed out and dropped packet");
                    break;
                }
                System.out.print(new String(data, 0, length));
                count += length;
            }
            while (count < data.length);

            System.out.println();
        }

        client.close();
public static final voidmain(java.lang.String[] args)


        if (args.length == 1)
        {
            try
            {
                echoTCP(args[0]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else if (args.length == 2 && args[0].equals("-udp"))
        {
            try
            {
                echoUDP(args[1]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else
        {
            System.err.println("Usage: echo [-udp] <hostname>");
            System.exit(1);
        }