Help. Multi Threading with sockets in client/server environment

[guenchy]

I'm having trouble introduce multi‐threading in SimpleServer.java. I need to make it so ther server can handle an arbitrary number of client connections simultaneously. That so, each time the server receives a new incoming client connection, spawn a new thread that will process that particular connection.

So I could implement a loop such as:

while(true){
try{
//server.accept returns a client connection
Thread t = new Thread(w);
t.start();
} catch (IOException e) {
System.exit(-1);
}

And implement it in the SimpleServer class around where I create a new Socket

Socket skt = myServerSocket.accept();

And than I'm not sure which code I have to move to the:
Publie void Run() method.

Here are the Sever and Client Classes. Sorry when I pasted it killed the formating..

Server Class

import java.io.;
import java.net.;
 
/
Simple server using Java Sockets.
 
/
public class SimpleServer {
 
/*
@param args
/
public static void main(String[] args) {
 
try {
// First we create a server socket and bind it to port 9999.
ServerSocket myServerSocket = new ServerSocket(9999);
 
// server processes incoming client connections forever...
while (true) {
 
// wait for an incoming connection...
System.out.println("Server is waiting for an incoming connection on host="
InetAddress.getLocalHost().getCanonicalHostName()
" port=" myServerSocket.getLocalPort());
 
Socket skt = myServerSocket.accept();
 
// ok, got a connection. Let's use java.io. niceties to read and write from the connection.
BufferedReader inputFromClient = new BufferedReader(new InputStreamReader(skt.getInputStream()));
PrintStream outputToClient = new PrintStream(skt.getOutputStream());
 
boolean connectionClosed = false;
while(!connectionClosed) {
// attempt to read input from the stream.
String buf = inputFromClient.readLine();
 
// if we got input, print it out and write a message back to the remote client..
if (buf != null) {
System.out.println("Server read: [" buf "]");
outputToClient.println(buf);
} else {
connectionClosed = true;
}
}
 
// close the connection.
skt.close();
System.out.println("Connection to client closed. Server is now going to wait for another connection.");
}
} catch (IOException ex) {
ex.printStackTrace();
System.out.println("Whoops, something bad happened! I'm outta here.");
}

Client Class

import java.io.;
import java.net.;
 
/*
Simple client using Java Sockets.
 
/
public class SimpleClient {
 
/*
@param args
/
public static void main(String[] args) {
 
// create a socket and find it to the host/port server is listening on.
String host;
int port;
 
if(args.length==0) {
host = "localhost";
port = 9999;
} else {
host = args[0];
String portStr = args[1];
try {
port = Integer.parseInt(portStr);
} catch (NumberFormatException nfe) {
System.out.println("Whoops, invalid port number. Will default to 9999");
port = 9999;
}
}
 
try {
System.out.println("Client will attempt connecting to server at host=" host " port=" port ".");
Socket skt = new Socket(host,port);
 
// ok, got a connection. Let's use java.io.* niceties to read and write from the connection.
BufferedReader myInput = new BufferedReader(new InputStreamReader(skt.getInputStream()));
BufferedReader consoleInput = new BufferedReader(new InputStreamReader(System.in));
 
PrintStream myOutput = new PrintStream(skt.getOutputStream());
 
boolean done = false;
 
while (!done) {
 
// prompt and read from console
System.out.print("Enter a message, or enter \"done\" to quit: ");
String buf = consoleInput.readLine();
 
if(buf != null) {
if(buf.equalsIgnoreCase("done")) {
done = true;
} else {
 
// write something to the server.
myOutput.println(buf);
 
// see if the server echoes it back.
buf = myInput.readLine();
if(buf != null) {
System.out.println("Client received [" buf + "] from the server!");
}
 
}
} else {
done = true;
}
}
 
// we're done, let's get out of dodge!
skt.close();
System.out.println("Client is exiting.");
 
 
} catch (IOException ex) {
ex.printStackTrace();
System.out.println("Whoops, something bad happened! I'm outta here.");
}
 
 
}
 
}
 
 
}
 
}

[Sunil Raghuvanshi]

Study this code and use it as the base for your server This code is working properly
Contact me if you have any query at sunil1raghu@gmail.com

import java.net.*;
import java.io.*;
/**
 *
 * @author Sunil Raghuvanshi
 */
public class MyServer
{
    private ServerSocket sk;
    private Socket ck;
    MyServer()
    {
        try
        {
            sk= new ServerSocket(3033);
            startListening();
        }catch(Exception e)
        {
            System.out.println(e);
        }
    }
    public void startListening()
    {
        try
        {
            while(true)
            {
              System.out.println("Server is listening");
              ck=sk.accept();
              System.out.println("A Client has been connected and diverted to" + ck.getPort());
              RequestProcessor rp;
              rp=new RequestProcessor(ck);
           }
        }catch(Exception e)
        {
            System.out.println(e);
        }
    }
    public static void main(String args[])
    {
        MyServer cs=new MyServer();
    }
}
class RequestProcessor extends Thread
{
    private Socket cc;
    RequestProcessor(Socket j)
    {
        cc=j;
        start();
    }
    public void run()
    {
        try
       {
            InputStream i;
            InputStreamReader ir;
            OutputStream o;
            OutputStreamWriter ow;
            StringBuffer sb;
            String s;
            System.out.println("Reading request stream");
            i=cc.getInputStream();
            ir=new InputStreamReader(i);
            sb=new StringBuffer();
            int x;
            while(true)
            {
                x=ir.read();
                if(x==-1 || x=='\n')
                {
                    break;
                }
                sb.append((char)x);
            }
            s=sb.toString();
            System.out.println("Request Stream"+s);
            int x1,x2;
            x1=s.indexOf(',');
            x2=s.indexOf(',',x1+1);
 
            String pc1,pc2,pc3;
            pc1=s.substring(0,x1);
            pc2=s.substring(x1+1,x2);
            pc3=s.substring(x2+1);
            System.out.println("Storing the data...");
            System.out.println("Roll Number"+pc1);
            System.out.println("Name"+pc2);
            System.out.println("Sex :"+pc3);
            RandomAccessFile raf=new RandomAccessFile(new File("C:\\student.txt"),"rw");
            raf.seek(raf.length());
            raf.writeBytes(pc1+"\n"+pc2+"\n"+pc3);
            raf.close();
            System.out.println("Sending Response");
            s="Record Saved\n";
            o=cc.getOutputStream();
            ow=new OutputStreamWriter(o);
            ow.write(s);
            ow.flush();
            ir.close();
            ow.close();
            cc.close();
        }catch(Exception e)
        {
            System.out.println(e);
        }
    }
}

Good Luck