Networking - Java 8 Recipes - page 846

tagramChannel is opened and bound to null . The null value is important be-
cause by setting the SocketAddress equal to null , the socket will be bound to an
address that is assigned automatically. Next, a ByteBuffer is created that contains a
message that will be broadcast to any listeners. The message is then sent using the Da-
tagramChannel 's send(ByteBuffer, InetSocketAddress) method. The
send() method in the solution accepts the message as a ByteBuffer object, as
well as a new InetSocketAddress that is created by using the address and port,
which was declared at the beginning of the block. Told you we'd get back to those!

server.send(message, new InetSocketAddress(address,
port));

At this point, the client would receive the message that was sent by the server. As
for the client that is demonstrated in the solution to this recipe, it would then discon-
nect. Normally in a real-world scenario, a different class would most likely initiate the
server, and its run() method would contain a loop that would continue to execute un-
til all messages have been broadcast or the loop was told to stop. The client would
probably not disconnect until after a user initiated a shutdown.

21-5. Generating and Reading from

URLs
Problem

You want to generate URLs programmatically in your application. Once the URLs
have been created, you'd like to read data from them for use in your application.

Solution

Make use of the java.net.URL class in order to create an URL. There are a few dif-
ferent ways to generate an URL depending on the address you are attempting to work
with. This solution demonstrates a few different ways to create URL objects, along
with comments indicating the differences. Once the URL objects have been created,
one of the URLs is read into a BufferedReader and printed to the command line.