Book Image

Spring Essentials

Book Image

Spring Essentials

Overview of this book

Spring is an open source Java application development framework to build and deploy systems and applications that run on the JVM. It is the industry standard and the most popular framework among Java developers with over two-thirds of developers using it. Spring Essentials makes learning Spring so much quicker and easier with the help of illustrations and practical examples. Starting from the core concepts of features such as inversion of Control Container and BeanFactory, we move on to a detailed look at aspect-oriented programming. We cover the breadth and depth of Spring MVC, the WebSocket technology, Spring Data, and Spring Security with various authentication and authorization mechanisms. Packed with real-world examples, you’ll get an insight into utilizing the power of Spring Expression Language in your applications for higher maintainability. You’ll also develop full-duplex real-time communication channels using WebSocket and integrate Spring with web technologies such as JSF, Struts 2, and Tapestry. At the tail end, you will build a modern SPA using EmberJS at the front end and a Spring MVC-based API at the back end.By the end of the book, you will be able to develop your own dull-fledged applications with Spring.
Table of Contents (14 chapters)
Spring Essentials
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Chapter 4. Understanding WebSocket

The idea of web applications was built upon a simple paradigm. In a unidirectional interaction, a web client sent a request to a server, the server replied to the request, and the client rendered the server's response. The communication started with a client-side request and ended with the server's response.

We built our web applications based on this paradigm; however, some drawbacks existed in the technology: the client had to wait for the server's response and refresh the browser to render it. This unidirectional nature of the communication required the client to initiate a request. Later technologies such as AJAX and long polling brought major advantages to our web applications. In AJAX, the client initiated a request but did not wait for the server's response. In an asynchronous manner, the AJAX client-side callback method got the data from the server and the browsers' new DHTML features rendered the data without refreshing the browser.

Apart from unidirectional...