FYI This is homework. I have to build a Java Chat server. I have been able to build a server which communicates with 1 client. But I need this to communicate with multiple users.
A user is supposed to type in the person's name they wish to talk to followed by a dash (-) and then the message to be sent. I am able to get users signed on but I am not able to get the list of users to print out or the messages to send to other users. Here is the server code:
/**
Threaded Server
*/
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Set;
public class ThreadedServer
{
public static void main( String[] args) throws Exception
{
HashMap<String, Socket> users = new HashMap<String, Socket>( );
ServerSocket server = new ServerSocket(5679);
System.out.println( "THE CHAT SERVER HAS STARTED! =)" );
while(true)
{
Socket client = server.accept();
ThreadedServer ser = new ThreadedServer();
ClientFromThread cft =ser.new ClientFromThread(client);
String name = cft.getUserName();
users.put( name, client );
cft.giveUsersMap( users );
//cft.giveOnlineUsers( ); //DOES NOT WORK YET!!!!
System.out.println("Threaded server connected to "
+ client.getInetAddress() + " USER: " + name );
}
}
//***************************************************************************************************
class ClientFromThread extends Thread
{
private Socket client;
private Scanner fromClient;
private PrintWriter toClient;
private String userName;
HashMap<String, Socket> users;
public ClientFromThread( Socket c ) throws Exception
{
client = c;
fromClient = new Scanner( client.getInputStream() );
toClient = new PrintWriter( client.getOutputStream(), true );
userName = getUser();
start();
}
public void giveUsersMap( HashMap<String, Socket> users )
{
this.users = users;
}
//THIS DOESNT WORK YET... IT PRINTS THE FIRST LINE BUT NOT THE LIST
public void giveOnlineUsers()
{
toClient.println("These users are currently online:");
Set<String> userList = users.keySet();
String[] userNames = null;
userList.toArray( userNames );
for( int i = 0; i< userNames.length; i++ )
{
toClient.println(userNames[i]);
}
}
public String getUserName()
{
return userName;
}
private String getUser()
{
String s = "";
while( (s.length() < 1) || (s == null) )
{
toClient.println("What is your first name? ");
s=fromClient.nextLine().trim();
}
toClient.println("Thank You! Welcome to the chat room " + s + ".");
return s.toUpperCase();
}
public void run()
{
String s = null;
String toUser;
String mesg;
while( (s=fromClient.nextLine().trim()) != null )
{
if( s.equalsIgnoreCase( "END" )) break;
for( int i=0; i<s.length(); i++)
{
if( s.charAt(i) == '-' )
{
toUser = s.substring( 0, i ).trim().toUpperCase();
mesg = s.substring( i+1 ).trim();
Socket client = users.get( toUser );
try
{
ClientToThread ctt = new ClientToThread(client);
ctt.sendMesg( mesg, toUser );
ctt.start();
}
catch(Exception e){e.printStackTrace();}
break;
}
if( (i+1) == s.length() )
{
toClient.println("Sorry the text was invalid. Please enter a user name " +
"followed by a dash (-) then your message.");
}
}
}
try
{
fromClient.close();
toClient.close();
client.close();
}
catch(Exception e){e.printStackTrace();}
}
} //end class ClientFromThread
//***************************************************************************************************
class ClientToThread extends Thread
{
private Socket client;
private PrintWriter toClient;
private String mesg;
public ClientToThread( Socket c ) throws Exception
{
client = c;
toClient = new PrintWriter( client.getOutputStream(), true );
}
public void sendMesg( String mesg, String userName )
{
this.mesg = userName + ": " + mesg;
}
public void run()
{
toClient.println(mesg);
try
{
toClient.close();
client.close();
}
catch(Exception e){e.printStackTrace();}
}
} //end class ClientToThread
//***************************************************************************************************
} //end class ThreadedServer
Here is the Client code"
import java.net.Socket;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
public class ReverseClient
{
public static void main( String[] args ) throws Exception
{
String line = null;
Socket server= new Socket( "10.0.2.103", 5679);
System.out.println( "Connected to host: " + server.getInetAddress() );
BufferedReader fromServer = new BufferedReader(
new InputStreamReader(server.getInputStream()) );
PrintWriter toServer = new PrintWriter( server.getOutputStream(), true );
BufferedReader input = new BufferedReader(
new InputStreamReader(System.in) );
while( (line=input.readLine()) !=null )
{
toServer.println(line);
System.out.println( fromServer.readLine() );
}
fromServer.close();
toServer.close();
input.close();
server.close();
}
}
Here is the console output (the top is the server, bottom is the client):
I am getting errors (as shown in the image above) and the messages are not sending. Any suggestions on how to take care of these issues?