how to access user inputted port number client-server

[rotaryfreak]

Hello,

Im building a client-server application and the user needs to input the hostName and the portNumber the client application and needs to send the portnumber to the server application. I have everything set up (properly, i think) but i keep getting a connection error on the portNumber because my instantiated portNumber is 0; On the server side, when i System.out.print the portNumber, i see it is in fact 0. I know why this is happening; its happening because the server is running before the client and the server is taking the default client's port number, but i dont know how to get around this.
Is there a way to ask the server to wait for the portNumber until the user has inputted the value?

here is my code: (for now i am concerned with the hostName and port number, the rest of the code doesn't do much. its supposed to take a client's string and the server is supposed to upper-case it and return it to the server... that functionality isn't completely working yet)

import java.io.*;
import java.net.*;
 
class TCPServer {
 
    static ServerSocket welcomeSocket;
    static Socket connectionSocket;
    static BufferedReader inFromClient;
    static DataOutputStream outToClient;
    static String clientSentence;
    static String capitalizedSentence;
 
    public static int getTCPClientPortNo(){
        return TCPClient.portNumber;
    }
 
    public static void receiveServerConnection(){
        try{
            System.out.println("The port number is: " + getTCPClientPortNo());
 
            welcomeSocket = new ServerSocket(getTCPClientPortNo());
        }
        catch(Exception e){
            System.out.println("The port number is not available");
        }
    }
 
    public static void acceptSocketConnection(){
        while (true) {
 
            try{
                connectionSocket = welcomeSocket.accept();
 
                inFromClient = new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
 
                outToClient = new DataOutputStream(connectionSocket.getOutputStream());
 
                clientSentence = inFromClient.readLine();
                System.out.println("clientSentence: " + clientSentence );
 
                capitalizedSentence = clientSentence.toUpperCase() + "\n";
 
                outToClient.writeBytes(capitalizedSentence);
            }
            catch(Exception e){
                System.out.println("Some error occured");
 
            }
 
        }
    }
 
 
    public static void main(String args[]) throws Exception {
 
        receiveServerConnection();
 
 
    }
}
 

and the client code is:

import java.io.*;
import java.net.*;
import java.util.*;
 
class TCPClient {
 
    static String host, port;
    static int portNumber = 0;
    static boolean connection = true;
 
    static Scanner kb = new Scanner(System.in);
    static Socket clientSocket;
 
    public static void getServerInfo(){
        try{
        System.out.print("Please enter the host name: ");
        BufferedReader hostInFromUser = new BufferedReader(new InputStreamReader(System.in));
        TCPClient.host = hostInFromUser.readLine();
        System.out.println("Host Name: " + TCPClient.host);
 
 
        System.out.print("Please enter the port number: ");
        BufferedReader portInFromUser = new BufferedReader(new InputStreamReader(System.in));
        TCPClient.port = portInFromUser.readLine();
        TCPClient.portNumber = Integer.parseInt(TCPClient.port);
        System.out.println("Port Number: " + TCPClient.portNumber);
 
        System.out.println("The client application will now attempt to connect to the server...");
 
        serverConnect(host, portNumber);
        }
        catch(Exception e){
            System.out.println("There has been an unexpecetd error, please try again...");
 
        }
    }
 
    public static void serverConnect(String hostName, int portNumber){
        try{
            clientSocket = new Socket(hostName, portNumber);
            System.out.println("Successfully connected to the server!");
            connection=true;
 
        }
        catch(Exception e){
            System.out.println("The connection to the server has been refused, please try again...");
            connection=false;
        }
    }
 
    public static void main(String args[]) throws Exception {
 
        String sentence;
        String modifiedSentence;
        do{
            TCPClient.getServerInfo();
 
        }
        while(TCPClient.connection ==false);
        {
            TCPClient.getServerInfo();
 
        }
        BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
 
 
        DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
 
        BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        sentence = inFromUser.readLine();
 
        outToServer.writeBytes(sentence + "\n");
 
        modifiedSentence = inFromServer.readLine();
 
        System.out.println("FROM SERVER: " + modifiedSentence);
 
        clientSocket.close();
    }
}
 

so again, the question is: is there a way to tell the server to wait until the user inputs the port number before the server gets it?

thanks a lot