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Categories / Java / Network Protocol
 

Connects to the default echo 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.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.InetAddress; import java.net.SocketException; import org.apache.commons.net.EchoTCPClient; import org.apache.commons.net.EchoUDPClient; /***  * 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.  * <p>  * Usage: echo [-udp] <hostname>  * <p>  ***/ public class echo {     public static final void echoTCP(String host) throws IOException     {         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 void echoUDP(String host) throws IOException     {         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 void main(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);         }     } }                     apache_net.zip( 395 k)