Enterprise Java

New in JAX-RS 2.0 – @BeanParam annotation

JAX-RS is awesome to say the least and one of my favorites! Why?

  • Feature rich
  • Intuitive (hence the learning curve is not as steep)
  • Easy-to-use and develop with
  • Has great RIs – Jersey, RestEasy etc

There are enough JAX-RS fans out there who can add to this!

JAX-RS 2.0 is the latest version of the JSR 311 specification and it was released along with Java EE 7.
 

Life without @BeanParam

Before JAX-RS 2.0, in order to pass/inject information from an HTTP request into JAX-RS resource implementation methods, one could

  1. Include multiple method arguments annotated with @FormParam, @PathParam, @QueryParam etc
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  3. Or, have a model class backed by JAXB/JSON or a custom MessageBodyReader implementation for JAX-RS Provider to be able to unmarshall the HTTP message body to a Java object – read more about this in one of my previous posts

 

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This means that something like a HTML5 based client would need to extract the FORM input, convert it into JSON or XML payload and then POST it over the wire.

Simplification in JAX-RS 2.0

This process has been simplified by introduction of the @BeanParam annotation. It helps inject custom value/domain/model objects into fields or method parameters of JAX-RS resource classes.

In case you want to refer to the code (pretty simple) or download the example/run it yourself, here is the GitHub link

All we need to do is, annotate the fields of the model (POJO) class with the injection annotations that already exist i.e. @PathParam, @QueryParam, @HeaderParam, @MatrixParam etc – basically any of the @xxxParam metadata types and

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Make sure that we include the @BeanParam annotation while injecting a reference variable of this POJO (only on METHOD, PARAMETER or FIELD).

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JAX-RS provider automatically constructs and injects an instance of your domain object which you can now use within your methods.

Just fill in the form information and POST it!

 
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That’s it. . . Short and Sweet!

Keep Coding!

Reference: New in JAX-RS 2.0 – @BeanParam annotation from our JCG partner Abhishek Gupta at the Object Oriented.. blog.
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Riccardo
9 years ago

That’s cool, I’ve missed something like this in JAX-RS 1, so much!

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