implements a multithreaded server that listens to port 8189 and echoes back all client input. : ServerSocket « Network Protocol « Java

1. Java
2. Network Protocol
3. ServerSocket

implements a multithreaded server that listens to port 8189 and echoes back all client input.

 
/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;

/**
   This program implements a multithreaded server that listens to port 8189 and echoes back 
   all client input.
   @author Cay Horstmann
   @version 1.20 2004-08-03
*/
public class ThreadedEchoServer
{  
   public static void main(String[] args )
   {  
      try
      {  
         int i = 1;
         ServerSocket s = new ServerSocket(8189);

         while (true)
         {  
            Socket incoming = s.accept();
            System.out.println("Spawning " + i);
            Runnable r = new ThreadedEchoHandler(incoming);
            Thread t = new Thread(r);
            t.start();
            i++;
         }
      }
      catch (IOException e)
      {  
         e.printStackTrace();
      }
   }
}

/**
   This class handles the client input for one server socket connection. 
*/
class ThreadedEchoHandler implements Runnable
{ 
   /**
      Constructs a handler.
      @param i the incoming socket
      @param c the counter for the handlers (used in prompts)
   */
   public ThreadedEchoHandler(Socket i)
   { 
      incoming = i; 
   }

   public void run()
   {  
      try
      {  
         try
         {
            InputStream inStream = incoming.getInputStream();
            OutputStream outStream = incoming.getOutputStream();
            
            Scanner in = new Scanner(inStream);         
            PrintWriter out = new PrintWriter(outStream, true /* autoFlush */);
            
            out.println( "Hello! Enter BYE to exit." );
            
            // echo client input
            boolean done = false;
            while (!done && in.hasNextLine())
            {  
               String line = in.nextLine();            
               out.println("Echo: " + line);            
               if (line.trim().equals("BYE"))
                  done = true;
            }
         }
         finally
         {
            incoming.close();
         }
      }
      catch (IOException e)
      {  
         e.printStackTrace();
      }
   }

   private Socket incoming;
}

   
  

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