Adding Web Services to Your Applications - JBoss AS 7 Development - page 251

Developing REST-based web services

JAX-RS (JSR-311) is a new JCP specification that provides a Java API for RESTful
web services in the HTTP protocol.

In their simplest form, RESTful web services are networked applications that manip-
ulate the state of system resources. In this context, resource manipulation means re-
source creation, retrieval, update, and deletion (CRUD). However, RESTful web ser-
vices are not limited to just these four basic data manipulation concepts. On the con-
trary, RESTful web services can execute logic at the server level, but, remember that
every result must be a resource representation of the domain.

The main difference with SOAP web services is that REST asks developers to use
HTTP methods explicitly and in a way that's consistent with the protocol definition.
This basic REST design principle establishes a one-to-one mapping between CRUD
operations and HTTP methods.

Therefore, with the delineated roles for resources and representations, we can now
map our CRUD actions to the HTTP methods POST , GET , PUT , and DELETE as fol-
lows:

Action HTTP protocol equivalent

RETRIEVE GET

CREATE POST

UPDATE PUT

DELETE DELETE