«
»
19
Feb

Echo Echo Echo…

Posted by Bernadet

This blog item has no other purpose than terrifying Lauren, as she will be switching to doing computer stuff in uni soon…just like me. She is now officially doomed. Here is my latest homework assignment, a multithreaded binary echo server using java (it doesn`t look very fancy because WP doesn`t indent):

MultiEchoServer.java

import java.net.*;
import java.io.*;
public class MultiEchoServer
{
ServerSocket socket;
public MultiEchoServer()
{
//Try to open a socket
try
{
socket = new ServerSocket(1337);
}
//Close the program if it fails
catch(IOException ioe)
{
System.out.println(“Server error, program terminating…”);
System.err.println(“Exception:  ” + ioe);
System.exit(1);
}
System.out.println(“Server started and listening…”);
while (true)
{
//Make a connection and start a thread
try
{
Socket client = socket.accept();
Thread t1 = new Thread(new ClientHandler(client));
t1.start();
}
//error handling
catch (IOException ioe)
{
System.err.println(“Exception:  ” + ioe);
}
}
}
public static void main (String[] args)
{
//make the server
new MultiEchoServer();
}
}
ClientHandler.java
import java.io.*;
import java.net.*;
//The class echothread is the actual thread, and is pretty much equal to the server class of the non multithreaded project.
class ClientHandler implements Runnable
{
Socket sock;
//initializing the socket
public ClientHandler(Socket s)
{
sock = s;
}
public void run()
{
try
{
//make the input and output stream
InputStream input = sock.getInputStream();
OutputStream output = sock.getOutputStream();
while (true)
{
//execute code while i does not equal -1
do
{
byte b;
while((b = (byte) input.read()) != -1)
{
output.write(b);
}
System.out.println(“system will now be terminated..”);
output.close();
input.close();
sock.close();
}while (true);
}
}
catch (IOException ioe)
{
System.err.println(“Exception:  ” + ioe);
}
}
}
MultiEchoClient.java
import java.net.*;
import java.io.*;
public class MultiEchoClient
{
public static void main(String[] args)
{
try
{
//make connection to server socket
Socket socket = new Socket(“127.0.0.1″, 1337);
OutputStream output = socket.getOutputStream();
InputStream input = socket.getInputStream();
//introduction message
System.out.println(“Hallo!”);
//execute code while i does not equal -1
do
{
byte b;
while ((b = (byte) System.in.read()) != -1)
{
output.write(b);
b = (byte) input.read();
String str = “”;
str += (char) b;
System.out.print(str);
}
System.out.println(“system will now be terminated..”);
output.close();
input.close();
socket.close();
}while (true);
}
//Error Handling
catch (IOException ioe)
{
System.err.println(“Exception:  ” + ioe);
}
}
}
Want to know what this does? Nothing but echo back to you what you type in the console. That`s right…you need all this code to make a computer say hi back to you after you said hi to him. BE AFRAID LAUREN, BE VERY AFRAID!!!!!
-Bernadet
Bernadet/19/The Netherlands - I was born on the 25th of september in a small town in the Netherlands. These days I study computer science and share this site with my sister...we create mayhem online together.
Bernadet
View all posts by Bernadet
Bernadets website

Tags: , , ,   Posted School |

2 Responses to “Echo Echo Echo…”

  1. CodeAddict Says:
    February 23rd, 2010 at 10:50 pm

    Actually, you don’t need all that code ;-)

    This will do the same (although it will be less verbose):

    EchoServer.java

    import java.io.*;
    import java.net.*;

    public class EchoServer {
    private class ClientHandler impements Runnable {
    private Socket socket;

    public ClientHandler (Socket socket) {
    this.socket = socket;
    }

    public void run () {
    try {
    int i;
    while ((i = socket.getInputStream().read()) != -1) {
    socket.getOutputStream().write(i);
    }
    } catch (IOException e) {
    e.printStackTrace();
    }
    }
    }

    public EchoServer () {
    try {
    ServerSocket socket = new ServerSocket(1337);
    while (true) {
    new Thread(new ClientHandler(socket.accept())).start();
    }
    } catch (IOException e) {
    e.printStackTrace();
    }
    }

    public static void main (String[] args) {
    new EchoServer();
    }
    }

    EchoClient.java

    import java.io.*;
    import java.net.*;

    public class EchoClient {
    public EchoClient (String host, int port) {
    try {
    Socket socket = new Socket(host, port);
    int i;
    while ((i = System.in.read()) != -1) {
    socket.getOutputStream().write(i);
    System.out.write(i);
    }
    } catch (IOException e) {
    e.printStackTrace();
    }
    }

    public static void main (String[] args) {
    new EchoClient("localhost", 1337);
    }
    }

  2. Bernadet Says:
    February 27th, 2010 at 8:14 pm

    True true, but that wouldn`t scare Lauren *grins*

Leave a Reply