Jakarta RESTful Web Services
Jakarta EE specification
Jakarta RESTful Web Services, (JAX-RS; formerly Java API for RESTful Web Services) is a Jakarta EE API specification that provides support in creating web services according to the Representational State Transfer (REST) architectural pattern. JAX-RS uses annotations, introduced in Java SE 5, to simplify the development and deployment of web service clients and endpoints.
From version 1.1 on, JAX-RS is an official part of Java EE 6. A notable feature of being an official part of Java EE is that no configuration is necessary to start using JAX-RS. For non-Java EE 6 environments a small entry in the web.xml deployment descriptor is required.
01Specification
JAX-RS provides some annotations to aid in mapping a resource class (a POJO) as a web resource. The annotations use the Java package jakarta.ws.rs (previously was javax.ws.rs but was renamed on May 19, 2019). They include:
- @Path specifies the relative path for a resource class or method.
- @GET, @POST, @PUT, @PATCH (since JAX-RS 2.1), @DELETE, @HEAD and @OPTIONS (since JAX-RS 1.1) specify the HTTP request type of a resource.
- @Produces specifies the response Internet media types (used for content negotiation).
- @Consumes specifies the accepted request Internet media types.
In addition, it provides further annotations to method parameters to pull information out of the request. All the @*Param annotations take a key of some form which is used to look up the value required.
- @PathParam binds the method parameter to a path segment.
- @QueryParam binds the method parameter to the value of an HTTP query parameter.
- @MatrixParam binds the method parameter to the value of an HTTP matrix parameter.
- @HeaderParam binds the method parameter to an HTTP header value.
- @CookieParam binds the method parameter to a cookie value.
- @FormParam binds the method parameter to a form value.
- @DefaultValue specifies a default value for the above bindings when the key is not found.
- @Context returns the entire context of the object (for example @Context HttpServletRequest request).
02JAX-RS 2.0
In January 2011 the JCP formed the JSR 339 expert group to work on JAX-RS 2.0. The main targets are (among others) a common client API and support for Hypermedia following the HATEOAS-principle of REST. In May 2013, it reached the Final Release stage.
On 2017-08-22 JAX-RS 2.1 specification final release was published. Main new supported features include server-sent events, reactive clients, and JSON-B.
03Implementations
Implementations of JAX-RS include:
- Apache CXF, an open source Web service framework
- Jersey, the reference implementation from Sun (now Oracle)
- RESTeasy, JBoss's implementation
- Restlet
- WebSphere Application Server from IBM:
- Version 7.0: via the "Feature Pack for Communications Enabled Applications"
- Version 8.0 onwards: natively
- WebLogic Application Server from Oracle, see notes
- Apache Tuscany (http://tuscany.apache.org/documentation-2x/sca-java-bindingrest.html), discontinued
- Cuubez framework (https://web.archive.org/web/20190707005602/http://cuubez.com/)
- Everrest, Codenvy's Implementation
- Jello-Framework, Java Application Framework optimized for Google App Engine, including a powerful RESTful engine and comprehensive Data Authorization model.
- Apache TomEE, an addition to Apache Tomcat
Sources and credits
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