Book Image

Developing Middleware in Java EE 8

Book Image

Developing Middleware in Java EE 8

Overview of this book

Middleware is the infrastructure in software based applications that enables businesses to solve problems, operate more efficiently, and make money. As the use of middleware extends beyond a single application, the importance of having it written by experts increases substantially. This book will help you become an expert in developing middleware for a variety of applications. The book starts off by exploring the latest Java EE 8 APIs with newer features and managing dependencies with CDI 2.0. You will learn to implement object-to-relational mapping using JPA 2.1 and validate data using bean validation. You will also work with different types of EJB to develop business logic, and with design RESTful APIs by utilizing different HTTP methods and activating JAX-RS features in enterprise applications. You will learn to secure your middleware with Java Security 1.0 and implement various authentication techniques, such as OAuth authentication. In the concluding chapters, you will use various test technologies, such as JUnit and Mockito, to test applications, and Docker to deploy your enterprise applications. By the end of the book, you will be proficient in developing robust, effective, and distributed middleware for your business.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Handling HTTP methods


As mentioned earlier, each HTTP request uses a request method, which in most cases is one of GET, POST, PUT, and DELETE. In RESTful architectures, those HTTP methods are usually used to perform actions based on the following convention:

  • GET: Request retrieval of an existing resource
  • POST: Request creation of a new resource
  • PUT: Request the updating of an existing resource, or create a new one if it does not exist
  • DELETE: Request deletion of an existing resource

In JAX-RS, a corresponding annotation for each HTTP method exists @GET, @POST, @PUT, and @DELETE. In the Handling JSON section, we will create a complete CRUD example for a RESTful service that performs creation, retrieval, updating, and deletion actions using those methods.

For now, let's try to use each of these methods in a simple example:

@Path("/hello") 
public class FirstRest { 
 
    @GET 
    public String testGet() { 
        return "You have issues a get request!"; 
    } 
 
    @POST 
    public String testPost...