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

DispatcherServlet explained


DispatcherServlet is the gateway to any Spring MVC application. Inherited from javax.servlet.http.HttpServlet, it is typically configured declaratively in the web.xml file. While you can have multiple definitions of DispatcherServlet with unique URL patterns, most Spring MVC applications only have single DispatcherServlet with the context-root URL(/), that is, all requests coming to that domain will be handled by DispatcherServlet.

Starting from Servlet 3.0, in addition to declarative configuration in the web.xml file, DispatcherServlet can be configured programmatically by implementing or extending either of these three support classes provided by Spring:

  • The WebAppInitializer interface

  • The AbstractDispatcherServletInitializer abstract class

  • The AbstractAnnotationConfigDispatcherServletInitializer abstract class

The following code listing demonstrates how to implement a WebAppInitializer directly in your application:

public class ApplicationInitializer implements...