NETWORKING - Introduction to Java Programming: Comprehensive Version - page 1149

create a thread for each connection. Here is how the server handles the establishment of a
connection:

while ( true ) {
Socket socket = serverSocket.accept(); // Connect to a client
Thread thread = new ThreadClass(socket);
thread.start();
}

The server socket can have many connections. Each iteration of the while loop creates a new
connection. Whenever a connection is established, a new thread is created to handle commu-
nication between the server and the new client, and this allows multiple connections to run at
the same time.
Listing 31.4 creates a server class that serves multiple clients simultaneously. For each con-
nection, the server starts a new thread. This thread continuously receives input (the radius of a
circle) from clients and sends the results (the area of the circle) back to them (see Figure 31.8).
The client program is the same as in Listing 31.2. A sample run of the server with two clients
is shown in Figure 31.9.

Server

A server socket
on a port

A socket for a
client

A socket for a
client

. . .

Client 1 Client n

F IGURE 31.8

Multithreading enables a server to handle multiple independent clients.

F IGURE 31.9

The server spawns a thread in order to serve a client.

L ISTING 31.4

MultiThreadServer.java
1 import java.io.*;
2 import java.net.*;
3 import java.util.Date;
4 import javafx.application.Application;
5 import javafx.application.Platform;
6 import javafx.scene.Scene;
7 import javafx.scene.control.ScrollPane;
8 import javafx.scene.control.TextArea;
9 import javafx.stage.Stage;
10