Socket client instance
The following GreetingClient is a client program that connects to the server via socket and sends a request, and then waits for a response.
// File name GreetingClient.java import java.net.*; import java.io.*; public class GreetingClient { public static void main(String [] args) { String serverName = args[0]; int port = Integer.parseInt(args[1]); try { System.out.println( "Connect to host: " + serverName + ", port number: " + port); Socket client = new Socket(serverName, port); System.out.println( "Remote host address: " + client.getRemoteSocketAddress()); OutputStream outToServer = client.getOutputStream(); DataOutputStream out = new DataOutputStream(outToServer); out.writeUTF("Hello from " + client.getLocalSocketAddress()); InputStream inFromServer = client.getInputStream(); DataInputStream in = new DataInputStream(inFromServer); System.out.println( "Server response: " + in.readUTF()); client.close(); }catch(IOException e) { e.printStackTrace (); } } }
Socket server instance
The following GreetingServer program is a server-side application that uses Socket to listen on a specified port.
// File name GreetingServer.java import java.net.*; import java.io.*; public class GreetingServer extends Thread { private ServerSocket serverSocket; public GreetingServer(int port) throws IOException { serverSocket = new ServerSocket(port); serverSocket.setSoTimeout(10000); } public void run() { while(true) { try { System.out.println( "Waiting for a remote connection, the port number is: " + serverSocket.getLocalPort() + "..." ); Socket server = serverSocket.accept(); System.out.println( "Remote host address: " + server.getRemoteSocketAddress()); DataInputStream in = new DataInputStream(server.getInputStream()); System.out.println(in.readUTF()); DataOutputStream out = new DataOutputStream(server.getOutputStream()); out.writeUTF( "Thank you for connecting me:" + server.getLocalSocketAddress() + "\nGoodbye!" ); server.close(); }catch(SocketTimeoutException s) { System.out.println("Socket timed out!"); break; }catch(IOException e) { e.printStackTrace (); break; } } } public static void main(String [] args) { int port = Integer.parseInt(args[0]); try { Thread t = new GreetingServer(port); t.run(); }catch(IOException e) { e.printStackTrace (); } } }