Interacting with Networks and Databases - Beginning Java 7 - page 794

Aftercreatinga Socket instance,andpossiblyinvoking bind() and connect()
onthatinstance,anapplicationtypicallyinvokes Socket 's InputStream getIn-
putStream() and OutputStream getOutputStream() methodstoobtainan
inputstreamforreadingbytesfromthesocketandanoutputstreamforwritingbytesto
thesocket.Also,theapplicationtypicallycalls Socket 's void close() methodto
close the socket once it no longer needs to perform input or output operations.
Thefollowingexampledemonstrateshowtocreateasocketthat'sboundtoportnum-
ber1500onthelocalhostandthenaccessitsinputandoutputstreams—exceptionsare
ignored for brevity:
Socket socket = new Socket("localhost", 1500);
InputStream is = socket.getInputStream();
OutputStream os = socket.getOutputStream();
I'vecreateda GetTime applicationthatdemonstratesthe Socket classbycreating
a socket to connect to an American National Institute of Standards & Technology
(NIST)timeservertoretrieveandoutputthecurrenttime. Listing9-1 presentsthisap-
plication's source code.

Listing 9-1. Getting and outputting the current time according to NIST's implementation of the
Daytime Protocol

import java.io.InputStream;
import java.io.IOException;

import java.net.Socket;
import java.net.UnknownHostException;

class GetTime
{

public static void main(String[] args)
{

if (args.length != 1)
{

System.err.println("usage : java GetTime serv-

er");

System.err.println("example: java GetTime

time.nist.gov");