Java™ How To Program (Early Objects), Tenth Edition

Client Class

The Client (Figs. 28.9–28.10) works similarly to class Server, except that the Client sends packets only when the user types a message in a text field and presses the Enter key. When this occurs, the program calls method actionPerformed (Fig. 28.9, lines 32–57), which converts the String the user entered into a byte array (line 41). Lines 44–45 create a DatagramPacket and initialize it with the byte array, the length of the String that was entered by the user, the IP address to which the packet is to be sent (InetAddress.getLocalHost() in this example) and the port number at which the Server is waiting for packets (5000 in this example). Line 47 sends the packet. The client in this example must know that the server is receiving packets ...