Book Image

Learning Network Programming with Java

Book Image

Learning Network Programming with Java

Overview of this book

Network-aware applications are becoming more prevalent and play an ever-increasing role in the world today. Connecting and using an Internet-based service is a frequent requirement for many applications. Java provides numerous classes that have evolved over the years to meet evolving network needs. These range from low-level socket and IP-based approaches to those encapsulated in software services. This book explores how Java supports networks, starting with the basics and then advancing to more complex topics. An overview of each relevant network technology is presented followed by detailed examples of how to use Java to support these technologies. We start with the basics of networking and then explore how Java supports the development of client/server and peer-to-peer applications. The NIO packages are examined as well as multitasking and how network applications can address practical issues such as security. A discussion on networking concepts will put many network issues into perspective and let you focus on the appropriate technology for the problem at hand. The examples used will provide a good starting point to develop similar capabilities for many of your network needs
Table of Contents (16 chapters)
Learning Network Programming with Java
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Channel support for UDP


The DatagramChannel class provides additional support for UDP. It can support nonblocking interchanges. The DatagramChannel class is derived from the SelectableChannel class that makes multithreaded application easier. We will examine its use in Chapter 7, Network Scalability.

The DatagramSocket class binds a channel to a port. After this class is used, it is no longer used directly. Using the DatagramChannel class means, we do not have to use datagram packets directly. Instead, data is transferred using an instance of the ByteBuffer class. This class provides several convenient methods to access its data.

To demonstrate the use of the DatagramChannel class, we will develop an echo server and client application. The server will wait for a message from a client, and then send it back to the client.

The UDP echo server application

The UDP echo server application declaration follows and uses port 9000. In the main method a try-with-resources block opens the channel and...