Server and Multiclient application

[Amruta Jegarkal]

Im working on Server and Multiclient application.....when server prints any line on client;control is not coming back to server unless client enters any data so how to make control to come back to server so that it can print next statement for client.......

[Lukasz Jarocki]

You need to use Threads and put every communication with client in another thread.

[Amruta Jegarkal]

Lukasz Jarocki wrote:You need to use Threads and put every communication with client in another thread.

Can you please explain me more precise how to implement as im not clear.....

[Lukasz Jarocki]

Well, show some effort, nobody won't write whole code. Just show which part of implemantation is difficult for you.

Basicaly all you need to do (on server side) is:
- create server socket and bind it
- wait for connection (accept method)
- then handle every new connection in new thread:

while(true)
{
     clientSocket = serverSocket.accept();
     new Thread((Runnable) new MyConnectionClass(clientSocket)).start();
}

[Amruta Jegarkal]

Lukasz Jarocki wrote:Well, show some effort, nobody won't write whole code. Just show which part of implemantation is difficult for you.

Basicaly all you need to do (on server side) is:
- create server socket and bind it
- wait for connection (accept method)
- then handle every new connection in new thread:

while(true)
{
     clientSocket = serverSocket.accept();
     new Thread((Runnable) new MyConnectionClass(clientSocket)).start();
}

I already did this much:

package com.simpragma.assignment.serverapplication;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashMap;

public class MultiClientServer {
	
	
	public static void main(String[] args) {
		
        try {
			ServerSocket serverSocket=new ServerSocket(1257);
			ArrayList<Object> arrayList=new ArrayList<Object>();
			//HashMap<Integer, Object> clientsList=new HashMap<Integer,Object>();
			HashMap<String,Socket> clients=new HashMap<String,Socket>();
			
			while(true)
			{   
				System.out.println("Waiting for connection");
				Socket socket=serverSocket.accept();
				System.out.println("Connection received from " + socket.getInetAddress().getHostName());
				clients.put(socket.getInetAddress().getHostName(), socket);
				new ServerThread(socket,clients).start();
				
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	

}

package com.simpragma.assignment.serverapplication;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

public class ServerThread extends Thread{

	Socket socket=null;
	//HashMap<Integer, Object> map=null;
	HashMap<String,Socket> clients=new HashMap<String,Socket>();
	OutputStream socketOut=null;
	InputStream socketIn=null;
	DataInputStream dis=null;
	DataOutputStream dos=null;
	public ServerThread(Socket socket,HashMap<String,Socket> clients) {
		this.socket=socket;
		this.clients=clients;
	}
	public ServerThread(Socket socket)
	{
		this.socket=socket;
	}
	public ServerThread() {
		// TODO Auto-generated constructor stub
	}
	@Override
	public void run() {
		try
		{
			socketIn=socket.getInputStream();
			socketOut=socket.getOutputStream();
			dis=new DataInputStream(socketIn);
			dos=new DataOutputStream(socketOut);
			/*dos.writeUTF("Server :Hello "+);
			String clientName=dis.readUTF();
			//clients.put(clientName, socket);
*/			dos.writeUTF("Server : Hello "+socket.getInetAddress().getHostName()+",below is the list of" +
					"people who are online");
			synchronized (this) {
				
			
			for (Map.Entry<String,Socket> entry: clients.entrySet()) {
				String client=entry.getKey();
				System.out.println("client "+client);
				dos.writeUTF(client);
				}
			}
			dos.writeUTF("Enter ur name,receiver name,msg to be sent");
			dos.writeUTF("Eg:Akshata,Amruta,hi hello");
			boolean flag=true;
			do
			{
		    String msg=dis.readUTF();
		    String message[]=msg.split(",");
		    String sender="",receiver="",actualMessage="";
		    
		    for(int i=0;i<message.length;i++)
		    {
		    	sender=message[0];
		    	receiver=message[1];
		    	actualMessage=message[2];
		    }
		    flag=sendMessage(sender,receiver,actualMessage);
			}while(flag);
	        
			
		}
		catch(IOException exception)
		{
			
		}
		
	}
	
	
	private boolean sendMessage(String sender, String receiver,
			String actualMessage) {
		boolean flag=true;
		if(actualMessage.equalsIgnoreCase("bye"))
		{
			flag=false;
		}
		
		for (Map.Entry<String,Socket> entry: clients.entrySet()) {
			String clientName=entry.getKey();
			if(clientName.equalsIgnoreCase(receiver))
			{
			     Socket socket=entry.getValue();
			     try {
					DataOutputStream receiverDOS=new DataOutputStream(socket.getOutputStream());
					receiverDOS.writeUTF(sender+" : "+actualMessage);
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			     
			}
			
	    }
		
		return flag;
	}
	
	
}

package com.simpragma.assignment.clientserverapplication.client;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;

public class Client {

	
	
	public static void main(String[] args) {
		
		// Open your connection to a server, at port 1254
		try
		{
	     Socket s1 = new Socket("localhost", 1257);
	     // Get an input file handle from the socket and read the input
	     InputStream s1In = s1.getInputStream();
	     DataInputStream dis = new DataInputStream(s1In);
	     
	     OutputStream s1Out=s1.getOutputStream();
	     DataOutputStream dos=new DataOutputStream(s1Out);
	     
	     String txt=null;
	     String st =null;
	     Scanner scanner=new Scanner(System.in);
	     do
	     {
	    	 st = new String (dis.readUTF());
		     System.out.println(st);
	         
			txt=scanner.nextLine();
			dos.writeUTF(txt);
			
			
			
	     }
	     while(!txt.equalsIgnoreCase("bye"));
	     dos.writeUTF("bye");
	     // When done, just close the connection and exit
	     dis.close();
	     s1In.close();
	     s1.close();
		}
		catch(IOException exception)
		{
			
		}
	   
	}

}

[Winston Gutkowski]

Amruta Jegarkal wrote:I already did this much...

Just for future reference, that's a heck of a lot of information to leave out.

Now...what was your question again? Have you run this? Does it compile? If you've run it, does it produce an error?

We're really floundering in the dark until you tell us what your specific problem is.

Winston

[Amruta Jegarkal]

Winston Gutkowski wrote:

Amruta Jegarkal wrote:I already did this much...

Just for future reference, that's a heck of a lot of information to leave out.

Now...what was your question again? Have you run this? Does it compile? If you've run it, does it produce an error?

We're really floundering in the dark until you tell us what your specific problem is.

Winston

This code is working fine,my question is when server sends something to client;until client reply server cannot send anything.....So i want client and sever to be independent in sending message.

[Winston Gutkowski]

Amruta Jegarkal wrote:This code is working fine,my question is when server sends something to client;until client reply server cannot send anything.....So i want client and sever to be independent in sending message.

In which case, you probably want to look at something like JMS, which supports asynchronous messaging; but I'd make certain you're sure about the rules before you do so. Do you really want your server bashing out messages into the ether if there's no likelihood of them ever being read?

Winston