Programming Forums > Application Development > Java

fresher · Jan 10th, 2007, 6:43 PM

Hi all, I've got this piece of code below which gives the output as shown:

// TCP client which receives a message from  server

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


class IPgenerator2
{

  //public static void main( String[] args )
 // {
  	//int n = 0; 
	String ip = "192.168.0.";
	void ipmethd()
	{
	
	
	KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		//to view  input
		//System.out.println(choice);
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			System.out.println("You selected to view machine with IP: 192.168.0.1");
 			//pass this ip to the client program to establish connection
 			break;
 	
 			case 2:
 			System.out.println("You selected to view machine with IP: 192.168.0.2");
 			break;
 	
 			default:
 			System.out.println("machine doesnt exist");
 			}
 	 
 	 	}
 	
     
}




//client program starts here

public class TCPclientText
{
	
	public static void main(String args[])
	{
		IPgenerator2 ip = new IPgenerator2();
	
		//call ipgenerator
		ip.ipmethd();
	
		//server IP address
 		  //String remoteIPaddress="192.168.2.4";
 		 // int remotePort=9000;
  

  //array to hold list of client IPs say registered
  //array enables me select the client to connect to
  String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
   int remotePort=9000;
   
  //for(int index=0; index<3;index++)
   
   try
       {
        // connect to server with remoteIPaddress on remotePort
        //Socket socket1 = new Socket( remoteIPaddress, remotePort );
        //here I have selected to connect to just the first client - index 0
        Socket socket1 = new Socket( remoteIPaddress[0], remotePort );
        
        
        //timeout after 3sec of inactivity
        //socket1.setSoTimeout(3000);
        
        // open reader to receive messages from server
        BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        System.out.println("Server contacted OK ");
        
        
        // loop reading messages from server
        while(true)                
            {
            	
            String line = inFromServer.readLine();
            System.out.println("From server " + line);
            }  
              
        }
        
        catch(UnknownHostException e){
            System.err.println("Don't know about host ....");    
            }       
        
        //predefined message is returned if client is not responding
        catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    //if server suddenly shutsdown for instance
    
     
}

}

// TCP client which receives a message from  server

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


class IPgenerator2
{

  //public static void main( String[] args )
 // {
  	//int n = 0; 
	String ip = "192.168.0.";
	void ipmethd()
	{
	
	
	KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		//to view  input
		//System.out.println(choice);
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			System.out.println("You selected to view machine with IP: 192.168.0.1");
 			//pass this ip to the client program to establish connection
 			break;
 	
 			case 2:
 			System.out.println("You selected to view machine with IP: 192.168.0.2");
 			break;
 	
 			default:
 			System.out.println("machine doesnt exist");
 			}
 	 
 	 	}
 	
     
}




//client program starts here

public class TCPclientText
{
	
	public static void main(String args[])
	{
		IPgenerator2 ip = new IPgenerator2();
	
		//call ipgenerator
		ip.ipmethd();
	
		//server IP address
 		  //String remoteIPaddress="192.168.2.4";
 		 // int remotePort=9000;
  

  //array to hold list of client IPs say registered
  //array enables me select the client to connect to
  String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
   int remotePort=9000;
   
  //for(int index=0; index<3;index++)
   
   try
       {
        // connect to server with remoteIPaddress on remotePort
        //Socket socket1 = new Socket( remoteIPaddress, remotePort );
        //here I have selected to connect to just the first client - index 0
        Socket socket1 = new Socket( remoteIPaddress[0], remotePort );
        
        
        //timeout after 3sec of inactivity
        //socket1.setSoTimeout(3000);
        
        // open reader to receive messages from server
        BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        System.out.println("Server contacted OK ");
        
        
        // loop reading messages from server
        while(true)                
            {
            	
            String line = inFromServer.readLine();
            System.out.println("From server " + line);
            }  
              
        }
        
        catch(UnknownHostException e){
            System.err.println("Don't know about host ....");    
            }       
        
        //predefined message is returned if client is not responding
        catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    //if server suddenly shutsdown for instance
    
     
}

}

OUTPUT:
1. 192.168.0.1
2. 192.168.0.2
3. 192.168.0.3
.
.
.
9. 192.168.0.9

SELECT FROM LIST OF IPS.........:

[b]QUESTION[\B]
Im trying to pass the choice of the user to the variable 'remoteIPaddress' so that a connection is established with the
IP address (host) selected from the list by the user. In order words if the user selects/ enters 2 then: 192.168.0.2 is passed / assigned to remoteIPadress. Im gonna delete the array remoteIPaddress[] if i can get this to work.
any responses will be appreciated. Thanks

Jimbo · Jan 10th, 2007, 8:48 PM

You can simply return the IP address selected from ipmethd() as a String, save that value in a variable, and use the variable when you create the socket.

fresher · Jan 10th, 2007, 9:27 PM

Hi thanks for your reply but i've tried something similar and it doesnt work. see below.

(Toggle Plain Text)

// TCP client which receives a message from  server

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


class IPgenerator2
{

  //public static void main( String[] args )
 // {
  	//int n = 0; 
  	String view_host;
	String ip = "192.168.2.";
	
	String ipmethd()
	{
	
	
	KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		
		
		
		//to view  input
		//System.out.println(choice);
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			view_host = "192.168.2.1";
 			System.out.println("You selected to view machine with IP: " + view_host);
 			return view_host;
 			break;
 	
 			case 2:
 			view_host = "192.168.2.2";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 			case 3:
 			view_host = "192.168.2.3";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 			case 4:
 			view_host = "192.168.2.4";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 	
 			default:
 			System.out.println("This machine doesnt exist, please choose a valid host");
 			return view_host;
 			break;
 			}
 		  }
 	 
 	 	
 	
     
}




//client program starts here

public class TCPclientText
{
	
	public static void main(String args[])
	{
		//initialisation
		String view_host; 
		IPgenerator2 ip = new IPgenerator2();
	
		//call ipgenerator
		ip.ipmethd();
	
	   
		//server IP address
 		  //String remoteIPaddress="192.168.2.4";
 		 // int remotePort=9000;
  
  
  
		  //array to hold list of client IPs say registered
 		 //array enables me select the client to connect to
 		// String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
  		String remoteIPaddress = ip.ipmethd();
   		int remotePort=9000;
   	
  		//for(int index=0; index<3;index++)
   
  		 try
       	{
        	// connect to server with remoteIPaddress on remotePort
        	//Socket socket1 = new Socket( remoteIPaddress, remotePort );
        	//here I have selected to connect to just the first client - index 0
        	Socket socket1 = new Socket( remoteIPaddress, remotePort );
        
        
        	//timeout after 3sec of inactivity
        	//socket1.setSoTimeout(3000);
        
        	// open reader to receive messages from server
        	BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        	System.out.println("Server contacted OK ");
        
        
        	// loop reading messages from server
        	while(true)                
            {
            	
            String line = inFromServer.readLine();
            System.out.println("From server " + line);
            }  
              
         }
        
        	catch(UnknownHostException e){
            System.err.println("Don't know about host ....");    
            }       
        
        //predefined message is returned if client is not responding
        catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    //if server suddenly shutsdown for instance
    
    
    } 
}

// TCP client which receives a message from  server

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


class IPgenerator2
{

  //public static void main( String[] args )
 // {
  	//int n = 0; 
  	String view_host;
	String ip = "192.168.2.";
	
	String ipmethd()
	{
	
	
	KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		
		
		
		//to view  input
		//System.out.println(choice);
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			view_host = "192.168.2.1";
 			System.out.println("You selected to view machine with IP: " + view_host);
 			return view_host;
 			break;
 	
 			case 2:
 			view_host = "192.168.2.2";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 			case 3:
 			view_host = "192.168.2.3";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 			case 4:
 			view_host = "192.168.2.4";
 			System.out.println("You selected to view machine with IP: " +  view_host);
 			return view_host;
 			break;
 			
 	
 			default:
 			System.out.println("This machine doesnt exist, please choose a valid host");
 			return view_host;
 			break;
 			}
 		  }
 	 
 	 	
 	
     
}




//client program starts here

public class TCPclientText
{
	
	public static void main(String args[])
	{
		//initialisation
		String view_host; 
		IPgenerator2 ip = new IPgenerator2();
	
		//call ipgenerator
		ip.ipmethd();
	
	   
		//server IP address
 		  //String remoteIPaddress="192.168.2.4";
 		 // int remotePort=9000;
  
  
  
		  //array to hold list of client IPs say registered
 		 //array enables me select the client to connect to
 		// String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
  		String remoteIPaddress = ip.ipmethd();
   		int remotePort=9000;
   	
  		//for(int index=0; index<3;index++)
   
  		 try
       	{
        	// connect to server with remoteIPaddress on remotePort
        	//Socket socket1 = new Socket( remoteIPaddress, remotePort );
        	//here I have selected to connect to just the first client - index 0
        	Socket socket1 = new Socket( remoteIPaddress, remotePort );
        
        
        	//timeout after 3sec of inactivity
        	//socket1.setSoTimeout(3000);
        
        	// open reader to receive messages from server
        	BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        	System.out.println("Server contacted OK ");
        
        
        	// loop reading messages from server
        	while(true)                
            {
            	
            String line = inFromServer.readLine();
            System.out.println("From server " + line);
            }  
              
         }
        
        	catch(UnknownHostException e){
            System.err.println("Don't know about host ....");    
            }       
        
        //predefined message is returned if client is not responding
        catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    //if server suddenly shutsdown for instance
    
    
    } 
}

Jimbo · Jan 10th, 2007, 11:28 PM

How is it not working? Does the BufferedReader line not work? Are you getting an exception? Is ip.ipmethd() not returning the correct value?

fresher · Jan 11th, 2007, 7:08 AM

Quote:

Originally Posted by Jimbo

How is it not working? Does the BufferedReader line not work? Are you getting an exception? Is ip.ipmethd() not returning the correct value?

Hi jimbo, thanks for your reply..this is what i've got:

(Toggle Plain Text)

// TCP client which receives a message from  server

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


	class IPgenerator2
	{
  		String view_host;
		String ip = "192.168.2.";
	
		String ipmethd()
		{
	
	
		KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		
		
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			view_host = "192.168.2.1";
 			//System.out.println("You selected to view machine with IP: " + view_host);
 			//return view_host = "192.168.2.1"; 
 			break;
 	
 			case 2:
 			view_host = "192.168.2.2";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.2";
 			break;
 			
 			case 3:
 			view_host = "192.168.2.3";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.3";
 			break;
 			
 			case 4:
 			view_host = "192.168.2.4";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.4";
 			break;
 			
 			
 			
 	
 			default:
 			System.out.println("This machine doesnt exist, please choose a valid host");
 			
 			return view_host;
 			}
 		// return view_host; 

 	    }
 	  }




	//client program starts here

	public class TCPclientText
	{
	
			public static void main(String args[])
			{
			//initialisation
			String view_host; 
			IPgenerator2 ip = new IPgenerator2();
	
			//call ipgenerator
			ip.ipmethd();
	
	   
			//server IP address
 		  	//String remoteIPaddress="192.168.2.4";
 		 	// int remotePort=9000;
  
  
  
			  //array to hold list of client IPs say registered
 			 //array enables me select the client to connect to
 			// String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
  			String remoteIPaddress = view_host;
   			int remotePort=9000;
   	
  			//for(int index=0; index<3;index++)
   
  			 try
       			{
        		// connect to server with remoteIPaddress on remotePort
        		//Socket socket1 = new Socket( remoteIPaddress, remotePort );
        		//here I have selected to connect to just the first client - index 0
        		Socket socket1 = new Socket( remoteIPaddress, remotePort );
        
        
        		//timeout after 3sec of inactivity
        		//socket1.setSoTimeout(3000);
        
        		// open reader to receive messages from server
        		BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        		System.out.println("Server contacted OK ");
        
        
        		// loop reading messages from server
        		while(true)                
            	{
            	
            	String line = inFromServer.readLine();
            	System.out.println("From server " + line);
            	}  
              
         	}
        
        		catch(UnknownHostException e){
            	System.err.println("Don't know about host ....");    
            	}       
        
        	//predefined message is returned if client is not responding
        	catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    	catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    	//if server suddenly shutsdown for instance
    
         }
    }
   	 
  	
the program for some reason calls 'ipmethd()' twice before actually connecting ie. as shown below

1.192.168.2.1
2.192.168.2.2
3.192.168.2.3
.
.
9. 192.168.2.9

Select the machine to view....:

//now when an input is entered say 4, the  ipmethd() is called again:

1.192.168.2.1
2.192.168.2.2
3.192.168.2.3
.
.
9. 192.168.2.9

Select the machine to view....:
//after entering an input here then it goes to the next step - connection

I cant figure out why it calls ipmethd() twice b4 connecting..
pls help me out here im confused. thanks n advance.

// TCP client which receives a message from  server

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


	class IPgenerator2
	{
  		String view_host;
		String ip = "192.168.2.";
	
		String ipmethd()
		{
	
	
		KeyboardInput in = new KeyboardInput();
	
		for(int i = 1; i < 10; i++) {
		System.out.print(i);
		System.out.print(". ");
		//System.out.print();
		System.out.println(ip + i);
		}
		System.out.println();
	
		System.out.print("SELECT A MACHINE TO VIEW FROM LIST: ");
		int choice = in.readInteger();
		
		
	
			switch (choice)
  		 	{ 
 	
 			case 1:
 			view_host = "192.168.2.1";
 			//System.out.println("You selected to view machine with IP: " + view_host);
 			//return view_host = "192.168.2.1"; 
 			break;
 	
 			case 2:
 			view_host = "192.168.2.2";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.2";
 			break;
 			
 			case 3:
 			view_host = "192.168.2.3";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.3";
 			break;
 			
 			case 4:
 			view_host = "192.168.2.4";
 			//System.out.println("You selected to view machine with IP: " +  view_host);
 			//return view_host = "192.168.2.4";
 			break;
 			
 			
 			
 	
 			default:
 			System.out.println("This machine doesnt exist, please choose a valid host");
 			
 			return view_host;
 			}
 		// return view_host; 

 	    }
 	  }




	//client program starts here

	public class TCPclientText
	{
	
			public static void main(String args[])
			{
			//initialisation
			String view_host; 
			IPgenerator2 ip = new IPgenerator2();
	
			//call ipgenerator
			ip.ipmethd();
	
	   
			//server IP address
 		  	//String remoteIPaddress="192.168.2.4";
 		 	// int remotePort=9000;
  
  
  
			  //array to hold list of client IPs say registered
 			 //array enables me select the client to connect to
 			// String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"};
  			String remoteIPaddress = view_host;
   			int remotePort=9000;
   	
  			//for(int index=0; index<3;index++)
   
  			 try
       			{
        		// connect to server with remoteIPaddress on remotePort
        		//Socket socket1 = new Socket( remoteIPaddress, remotePort );
        		//here I have selected to connect to just the first client - index 0
        		Socket socket1 = new Socket( remoteIPaddress, remotePort );
        
        
        		//timeout after 3sec of inactivity
        		//socket1.setSoTimeout(3000);
        
        		// open reader to receive messages from server
        		BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream()));
        		System.out.println("Server contacted OK ");
        
        
        		// loop reading messages from server
        		while(true)                
            	{
            	
            	String line = inFromServer.readLine();
            	System.out.println("From server " + line);
            	}  
              
         	}
        
        		catch(UnknownHostException e){
            	System.err.println("Don't know about host ....");    
            	}       
        
        	//predefined message is returned if client is not responding
        	catch(ConnectException e){
            System.err.println("Unreachable node!, failure in connecting to server"); 
            }    
        
    	catch (IOException e) {System.err.println("TCP client error " +  e); }
    
    	//if server suddenly shutsdown for instance
    
         }
    }
   	 
  	
the program for some reason calls 'ipmethd()' twice before actually connecting ie. as shown below

1.192.168.2.1
2.192.168.2.2
3.192.168.2.3
.
.
9. 192.168.2.9

Select the machine to view....:

//now when an input is entered say 4, the  ipmethd() is called again:

1.192.168.2.1
2.192.168.2.2
3.192.168.2.3
.
.
9. 192.168.2.9

Select the machine to view....:
//after entering an input here then it goes to the next step - connection

I cant figure out why it calls ipmethd() twice b4 connecting..
pls help me out here im confused. thanks n advance.

fresher · Jan 11th, 2007, 7:31 AM

many thanks indeed it now works.

Jan 10th, 2007, 6:43 PM	#1
fresher Newbie Join Date: Dec 2006 Posts: 13 Rep Power: 0	Passing a string to a variable Hi all, I've got this piece of code below which gives the output as shown: (Toggle Plain Text) // TCP client which receives a message from server import java.io.; import java.util.; import java.net.; class IPgenerator2 { //public static void main( String[] args ) // { //int n = 0; String ip = "192.168.0."; void ipmethd() { KeyboardInput in = new KeyboardInput(); for(int i = 1; i < 10; i++) { System.out.print(i); System.out.print(". "); //System.out.print(); System.out.println(ip + i); } System.out.println(); System.out.print("SELECT A MACHINE TO VIEW FROM LIST: "); int choice = in.readInteger(); //to view input //System.out.println(choice); switch (choice) { case 1: System.out.println("You selected to view machine with IP: 192.168.0.1"); //pass this ip to the client program to establish connection break; case 2: System.out.println("You selected to view machine with IP: 192.168.0.2"); break; default: System.out.println("machine doesnt exist"); } } } //client program starts here public class TCPclientText { public static void main(String args[]) { IPgenerator2 ip = new IPgenerator2(); //call ipgenerator ip.ipmethd(); //server IP address //String remoteIPaddress="192.168.2.4"; // int remotePort=9000; //array to hold list of client IPs say registered //array enables me select the client to connect to String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"}; int remotePort=9000; //for(int index=0; index<3;index++) try { // connect to server with remoteIPaddress on remotePort //Socket socket1 = new Socket( remoteIPaddress, remotePort ); //here I have selected to connect to just the first client - index 0 Socket socket1 = new Socket( remoteIPaddress[0], remotePort ); //timeout after 3sec of inactivity //socket1.setSoTimeout(3000); // open reader to receive messages from server BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream())); System.out.println("Server contacted OK "); // loop reading messages from server while(true) { String line = inFromServer.readLine(); System.out.println("From server " + line); } } catch(UnknownHostException e){ System.err.println("Don't know about host ...."); } //predefined message is returned if client is not responding catch(ConnectException e){ System.err.println("Unreachable node!, failure in connecting to server"); } catch (IOException e) {System.err.println("TCP client error " + e); } //if server suddenly shutsdown for instance } } // TCP client which receives a message from server import java.io.; import java.util.; import java.net.; class IPgenerator2 { //public static void main( String[] args ) // { //int n = 0; String ip = "192.168.0."; void ipmethd() { KeyboardInput in = new KeyboardInput(); for(int i = 1; i < 10; i++) { System.out.print(i); System.out.print(". "); //System.out.print(); System.out.println(ip + i); } System.out.println(); System.out.print("SELECT A MACHINE TO VIEW FROM LIST: "); int choice = in.readInteger(); //to view input //System.out.println(choice); switch (choice) { case 1: System.out.println("You selected to view machine with IP: 192.168.0.1"); //pass this ip to the client program to establish connection break; case 2: System.out.println("You selected to view machine with IP: 192.168.0.2"); break; default: System.out.println("machine doesnt exist"); } } } //client program starts here public class TCPclientText { public static void main(String args[]) { IPgenerator2 ip = new IPgenerator2(); //call ipgenerator ip.ipmethd(); //server IP address //String remoteIPaddress="192.168.2.4"; // int remotePort=9000; //array to hold list of client IPs say registered //array enables me select the client to connect to String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"}; int remotePort=9000; //for(int index=0; index<3;index++) try { // connect to server with remoteIPaddress on remotePort //Socket socket1 = new Socket( remoteIPaddress, remotePort ); //here I have selected to connect to just the first client - index 0 Socket socket1 = new Socket( remoteIPaddress[0], remotePort ); //timeout after 3sec of inactivity //socket1.setSoTimeout(3000); // open reader to receive messages from server BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream())); System.out.println("Server contacted OK "); // loop reading messages from server while(true) { String line = inFromServer.readLine(); System.out.println("From server " + line); } } catch(UnknownHostException e){ System.err.println("Don't know about host ...."); } //predefined message is returned if client is not responding catch(ConnectException e){ System.err.println("Unreachable node!, failure in connecting to server"); } catch (IOException e) {System.err.println("TCP client error " + e); } //if server suddenly shutsdown for instance } } OUTPUT: 1. 192.168.0.1 2. 192.168.0.2 3. 192.168.0.3 . . . 9. 192.168.0.9 SELECT FROM LIST OF IPS.........: [b]QUESTION[\B] Im trying to pass the choice of the user to the variable 'remoteIPaddress' so that a connection is established with the IP address (host) selected from the list by the user. In order words if the user selects/ enters 2 then: 192.168.0.2 is passed / assigned to remoteIPadress. Im gonna delete the array remoteIPaddress[] if i can get this to work. any responses will be appreciated. Thanks

Jan 10th, 2007, 8:48 PM	#2
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 769 Rep Power: 3	You can simply return the IP address selected from ipmethd() as a String, save that value in a variable, and use the variable when you create the socket. __________________ <insert disclaimer here> <insert shameless plug for Visual Studio here>

Jan 10th, 2007, 11:28 PM	#4
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 769 Rep Power: 3	How is it not working? Does the BufferedReader line not work? Are you getting an exception? Is ip.ipmethd() not returning the correct value? __________________ <insert disclaimer here> <insert shameless plug for Visual Studio here>

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Jan 10th, 2007, 9:27 PM	#3
fresher Newbie Join Date: Dec 2006 Posts: 13 Rep Power: 0	Hi thanks for your reply but i've tried something similar and it doesnt work. see below. (Toggle Plain Text) // TCP client which receives a message from server import java.io.; import java.util.; import java.net.; class IPgenerator2 { //public static void main( String[] args ) // { //int n = 0; String view_host; String ip = "192.168.2."; String ipmethd() { KeyboardInput in = new KeyboardInput(); for(int i = 1; i < 10; i++) { System.out.print(i); System.out.print(". "); //System.out.print(); System.out.println(ip + i); } System.out.println(); System.out.print("SELECT A MACHINE TO VIEW FROM LIST: "); int choice = in.readInteger(); //to view input //System.out.println(choice); switch (choice) { case 1: view_host = "192.168.2.1"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 2: view_host = "192.168.2.2"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 3: view_host = "192.168.2.3"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 4: view_host = "192.168.2.4"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; default: System.out.println("This machine doesnt exist, please choose a valid host"); return view_host; break; } } } //client program starts here public class TCPclientText { public static void main(String args[]) { //initialisation String view_host; IPgenerator2 ip = new IPgenerator2(); //call ipgenerator ip.ipmethd(); //server IP address //String remoteIPaddress="192.168.2.4"; // int remotePort=9000; //array to hold list of client IPs say registered //array enables me select the client to connect to // String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"}; String remoteIPaddress = ip.ipmethd(); int remotePort=9000; //for(int index=0; index<3;index++) try { // connect to server with remoteIPaddress on remotePort //Socket socket1 = new Socket( remoteIPaddress, remotePort ); //here I have selected to connect to just the first client - index 0 Socket socket1 = new Socket( remoteIPaddress, remotePort ); //timeout after 3sec of inactivity //socket1.setSoTimeout(3000); // open reader to receive messages from server BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream())); System.out.println("Server contacted OK "); // loop reading messages from server while(true) { String line = inFromServer.readLine(); System.out.println("From server " + line); } } catch(UnknownHostException e){ System.err.println("Don't know about host ...."); } //predefined message is returned if client is not responding catch(ConnectException e){ System.err.println("Unreachable node!, failure in connecting to server"); } catch (IOException e) {System.err.println("TCP client error " + e); } //if server suddenly shutsdown for instance } } // TCP client which receives a message from server import java.io.; import java.util.; import java.net.; class IPgenerator2 { //public static void main( String[] args ) // { //int n = 0; String view_host; String ip = "192.168.2."; String ipmethd() { KeyboardInput in = new KeyboardInput(); for(int i = 1; i < 10; i++) { System.out.print(i); System.out.print(". "); //System.out.print(); System.out.println(ip + i); } System.out.println(); System.out.print("SELECT A MACHINE TO VIEW FROM LIST: "); int choice = in.readInteger(); //to view input //System.out.println(choice); switch (choice) { case 1: view_host = "192.168.2.1"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 2: view_host = "192.168.2.2"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 3: view_host = "192.168.2.3"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; case 4: view_host = "192.168.2.4"; System.out.println("You selected to view machine with IP: " + view_host); return view_host; break; default: System.out.println("This machine doesnt exist, please choose a valid host"); return view_host; break; } } } //client program starts here public class TCPclientText { public static void main(String args[]) { //initialisation String view_host; IPgenerator2 ip = new IPgenerator2(); //call ipgenerator ip.ipmethd(); //server IP address //String remoteIPaddress="192.168.2.4"; // int remotePort=9000; //array to hold list of client IPs say registered //array enables me select the client to connect to // String remoteIPaddress[]={"192.168.2.4","192.168.2.5","192.168.2.6"}; String remoteIPaddress = ip.ipmethd(); int remotePort=9000; //for(int index=0; index<3;index++) try { // connect to server with remoteIPaddress on remotePort //Socket socket1 = new Socket( remoteIPaddress, remotePort ); //here I have selected to connect to just the first client - index 0 Socket socket1 = new Socket( remoteIPaddress, remotePort ); //timeout after 3sec of inactivity //socket1.setSoTimeout(3000); // open reader to receive messages from server BufferedReader inFromServer = new BufferedReader(new InputStreamReader( socket1.getInputStream())); System.out.println("Server contacted OK "); // loop reading messages from server while(true) { String line = inFromServer.readLine(); System.out.println("From server " + line); } } catch(UnknownHostException e){ System.err.println("Don't know about host ...."); } //predefined message is returned if client is not responding catch(ConnectException e){ System.err.println("Unreachable node!, failure in connecting to server"); } catch (IOException e) {System.err.println("TCP client error " + e); } //if server suddenly shutsdown for instance } }

Jan 11th, 2007, 7:31 AM	#6
fresher Newbie Join Date: Dec 2006 Posts: 13 Rep Power: 0	many thanks indeed it now works.

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Passing a string to a variable