jm2dev writes "The title is self descriptive, you will learn what a REST architecture is, the concepts behind it, advantages and constraints, and how to implement web services in a RESTful way serving and consuming content using the Java programming language, as command line applications, desktop graphical client, run by an application server or even as standalone applications. Almost everything you need to know to start working with web services in Java the REST way is covered by this book." Read on for the rest of Jose's review.No previous knowledge about REST is required, as the author presents a good introduction to Representational State Transfer; although the reader is supposed to understand the Java language syntax as you can expect because of the title. Any further familiarities are not needed, because to use the code samples only the Java Development Kit is required, so you can try it and play with it on any computer with a java SDK, like OpenJDK 6, installed and configured, with your favorite plain text editor or with a fully featured modern IDE.
The book starts with an introduction to the REST software architectural style. The concepts behind REST, their main components, constraints and ideas that made a software system RESTful. The details of the HTTP requests and responses interchanged by clients and servers are explained. And the role that REST services play in Service Oriented Architectures is discussed.
Next, several clients to consume web services using the Twitter messaging API are explained and the simplicity to consume REST web services will encourage readers to experiment with other REST web services available in Internet.
The ability to retrieve information from more than one web service is a nice feature practically implemented as a simple mashup in the third chapter. A web page displays the results obtained by requests to Google, Yahoo, Twitter and TextWise's SemanticHacker REST web services.
Now that the way to consume information provided by REST web services has been explained, it's time to start thinking about the other part of the equation: considerations to design a REST web service are introduced, discussed, and a simple microblogging solution is developed and used during the next chapters. From my point of view this part is very useful, as the author has done a good job providing a reusable solution, and remarking how important is in modern software development to provide a smart design that can fit different scenarios with minimum modifications.
Readers will be able to implement a single desktop client, to perform those actions, and although this approach looks like has lost popularity among developers, this section will be useful for those developers that are in the need to create a desktop client instead of a web based one.
Clients need servers to consume information from, and the next chapters describe popular frameworks like Restlet (both versions 1.1 and 2.0), Sun's Jersey (now Oracle's) and JBoss' Resteasy, with a clear emphasis on their usage of JAX-RS implementation, and finally Struts 2 with the REST plugin. How the same REST web service can be implemented using any of them is a worthy reminder of the fact that properly modularized software provides a valuable way to reuse existing code. The author tries to be neutral but he highlighted important aspects to consider before choosing any of them like, as the features they provide can fit better different scenarios.
Although a client consuming web services have been implementing as a desktop client and as a web based client using servlets and JSP pages, the introduced frameworks provide a simpler way to implement clients, which is very handful because they are needed to test our web services work as we expect. Regarding this aspect, developed in chapter nine, I miss a chapter talking about REST web services testing that can be used in continuous integration environment to automate our tests.
Finally, additional topics are treated like authentication and security, which aren't essential to get the basic functionality, but are needed frequently in real world applications and here you will find a nice introduction to those topics.
I found this book very well structured, starting with an introduction to REST concepts and architecture, its advantages and constraints, and a comparison against other alternatives. Complexity is managed terrifically, as readers see their questions answered with working solutions, that can be easily tested in a computer with a working java development environment. Starting with how to query popular web services with a browser, and later on implementing our first and simple clients and servers with widely used open source frameworks.
From my point of view, Java developers with no experience in REST architectures will find this book specially useful, despite your experience the book provides a good explanation of well designed architectures and how important they are to achieve a working, elegant and easy to maintain solution, and this aspect is exposed with working and useful implementations.
Packt Publishing books are characterized by a well formatted text with easy to understand language and at the same time being precise. It is these facts that make even this technical book a pleasurable reading experience.
The code provided through out all the book are easy to understand and implement. Here the author made a good work explaining the key concepts and how they are translated into code. Furthermore, in order to be practical, the needed Java libraries are provided, almost eliminating the chance to incur in compilation errors. Of course, a working implementation can be downloaded for those of the reader who prefer not to type more than the essential.
Jose Miguel is a java software developer and open source enthusiast based in London. @jm2dev
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