Connects to the default chargen service port
/*
* Copyright 2001-2005 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package examples;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.net.InetAddress;
import java.net.SocketException;
import org.apache.commons.net.CharGenTCPClient;
import org.apache.commons.net.CharGenUDPClient;
/***
* This is an example program demonstrating how to use the CharGenTCPClient
* and CharGenUDPClient classes. This program connects to the default
* chargen service port of a specified server, then reads 100 lines from
* of generated output, writing each line to standard output, and then
* closes the connection. The UDP invocation of the program sends 50
* datagrams, printing the reply to each.
* The default is to use the TCP port. Use the -udp flag to use the UDP
* port.
* <p>
* Usage: chargen [-udp] <hostname>
* <p>
***/
public class chargen
{
public static final void chargenTCP(String host) throws IOException
{
int lines = 100;
String line;
CharGenTCPClient client = new CharGenTCPClient();
BufferedReader chargenInput;
// We want to timeout if a response takes longer than 60 seconds
client.setDefaultTimeout(60000);
client.connect(host);
chargenInput =
new BufferedReader(new InputStreamReader(client.getInputStream()));
// We assume the chargen service outputs lines, but it really doesn't
// have to, so this code might actually not work if no newlines are
// present.
while (lines-- > 0)
{
if ((line = chargenInput.readLine()) == null)
break;
System.out.println(line);
}
client.disconnect();
}
public static final void chargenUDP(String host) throws IOException
{
int packets = 50;
byte[] data;
InetAddress address;
CharGenUDPClient client;
address = InetAddress.getByName(host);
client = new CharGenUDPClient();
client.open();
// If we don't receive a return packet within 5 seconds, assume
// the packet is lost.
client.setSoTimeout(5000);
while (packets-- > 0)
{
client.send(address);
try
{
data = client.receive();
}
// 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");
continue;
}
catch (InterruptedIOException e)
{
// We timed out and assume the packet is lost.
System.err.println(
"InterruptedIOException: Timed out and dropped packet");
continue;
}
System.out.write(data);
System.out.flush();
}
client.close();
}
public static final void main(String[] args)
{
if (args.length == 1)
{
try
{
chargenTCP(args[0]);
}
catch (IOException e)
{
e.printStackTrace();
System.exit(1);
}
}
else if (args.length == 2 && args[0].equals("-udp"))
{
try
{
chargenUDP(args[1]);
}
catch (IOException e)
{
e.printStackTrace();
System.exit(1);
}
}
else
{
System.err.println("Usage: chargen [-udp] <hostname>");
System.exit(1);
}
}
}
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