Sockets for Servers - Java Network Programming - page 287

more reasons, you cannot rely on clients to close sockets, even when the protocol re‐
quires them to, which this one doesn't.
Example 9-1 puts this all together. It uses Java 7's try-with-resources to autoclose the
sockets.
Example 9-1. A daytime server
import java.net.* ;
import java.io.* ;
import java.util.Date ;
public class DaytimeServer {
public final static int PORT = 13 ;
public static void main ( String [] args ) {
try ( ServerSocket server = new ServerSocket ( PORT )) {
while ( true ) {
try ( Socket connection = server . accept ()) {
Writer out = new OutputStreamWriter ( connection . getOutputStream ());
Date now = new Date ();
out . write ( now . toString () + "\r\n" );
out . flush ();
connection . close ();
} catch ( IOException ex ) {}
}
} catch ( IOException ex ) {
System . err . println ( ex );
}
}
}
The class has a single method, main() , which does all the work. The outer try block
traps any IOException s that may arise while the ServerSocket object server is con‐
structed on the daytime port. The inner try block watches for exceptions thrown while
the connections are accepted and processed. The accept() method is called within an
infinite loop to watch for new connections; like many servers, this program never ter‐
minates but continues listening until an exception is thrown or you stop it manually.
The command for stopping a program manually depends on your
system; under Unix, Windows, and many other systems, Ctrl-C will
do the job. If you are running the server in the background on a Unix
system, stop it by finding the server's process ID and killing it with the
kill command ( kill pid ) .