Jax Rs

Common use-case in web-application development is aggregating data from multiple resources, combining them together and returning them to the used as XML/JSON or as a web page. In Java world these (external) resources can be approached via standardized Clients from JAX-RS 2.0. Jersey 2 application can use so-called managed client mechanism that brings a convenient way to create JAX-RS clients and web targets for such resources.

In this article we’ll create a simple Jersey application deploy it in Jetty servlet container and everything will be hosted on Heroku.

Create an Application

To create a skeleton of Jersey 2 web-app that can be run on Heroku from the jersey-heroku-webapp archetype (available since Jersey 2.5), execute the following Maven command in the directory where you want the new project should be located:

mvn archetype:generate -DarchetypeArtifactId=jersey-heroku-webapp \
    -DarchetypeGroupId=org.glassfish.jersey.archetypes -DinteractiveMode=false \
    -DgroupId=com.example -DartifactId=simple-heroku-webapp -Dpackage=com.example \
    -DarchetypeVersion=2.5.1

Adjust the groupId, package and/or artifactId of your new web application project to your needs or, alternatively, you can change it by updating the new project pom.xml once it gets generated.

When you register providers (such as filters and interceptors) in your application they’re associated and applied to each resource method by default. In other words they’re bound globally. For most cases this approach is sufficient but sometimes, especially when you want to use your provider only with a few methods, it’s not enough. JAX-RS 2.0 brings a solution for this situation: Name and Dynamic Binding.

There has been some confusion on StackOverflow lately about how to register JAX-RS resource classes and custom providers in Jersey 2. The main problem seemed to be finding and using correct properties and methods to configure a JAX-RS/Jersey application. In this article I’d like to discuss 3 ways how to configure such an application properly.