GsonJerseyProviderExample

GsonJerseyBodyParser

GsonJerseyProvider is an example on how to use the Google Gson Library as an Provider on Jersey JAX-RS applications.

The original Version of the GsonJerseyProvidor.java can be found here: @eclipsesource:

Creating modern applications often involves consuming REST based web services. One of the more popular ways to publish a REST service in Java is the JAX-RS (Jersey) specification. It allows you to very easily enhance your REST resources with Java annotations.

by Moritz Post.

I needed an working example, because I had some issues getting started only with his class and I couldn't just leave it dead on my disk.

The configuration part

First to get the class of Moritz Post running we need to do a little bit of configuration so Jersey knows to load the provider (web.xml):

<servlet>
	<servlet-name>Services</servlet-name>
	<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
	<init-param>
		<param-name>jersey.config.server.provider.packages</param-name>
		<param-value>
  			com.dominikangerer.gson.provider.v1.util,
  			com.dominikangerer.gson.provider.v1.controller
  		</param-value>
	</init-param>
	<init-param>
		<param-name>jersey.config.server.provider.scanning.recursive</param-name>
		<param-value>false</param-value>
	</init-param>
	<load-on-startup>1</load-on-startup>
</servlet>

Now you should be able to run the example from Moritz Post but you will have to add the GsonUtil to get the version I provided in this repository as well - so let me explain it a little bit to you.

GsonUtil

In this GsonUtil I added the DateFormat yyyy-MM-dd'T'HH:mm:ss.SSSXX as default DateFormat to Gson by adding new registerTypeAdapter for serializing and deserializing. I also added the possibility to load a preconfigurated instance of Gson to show only properties with @Expose Annotation.

Container

Why? Javascipt Frameworks like Ember can be used with an RESTAdapter which provide such an pattern of responses - so why not return such an formated Json?

In this Repository you can find an simple Controller for GETting an List<Resource> and simply GET an Resource by id. To Achieve this on an structured way I added an new container package which can be used for resources and also for an single resource. It also capsules the whole Response.status(Response.Status.X).entity(Y).build(); stuff for you so you can simply use it like this in your Controller to return the action you performed with the right success status:

return ResourceContainer.ok();
return ResourceContainer.ok(Resource);
return ResourceContainer.ok(Resource List);
return ResourceContainer.ok(Resource ArrayList);
return ResourceContainer.ok(Resource Collection);
return ResourceContainer.updated();
return ResourceContainer.updated(Resource);
return ResourceContainer.created(Resource);
return ResourceContainer.deleted();

Version

1.0.1

Installation

You need an Container like Tomcat and clone this repository:

git clone git@github.com:DominikAngerer/java-GsonJerseyProvider.git

Import it into your favourite IDE (i'm using Eclipse Luna) and enjoy.

Calls

Don't mind if you get an 404 on path: /. Now it will return: Okay, I hated the 404 Page here ;), because I really did.

• Get List of Resources http://localhost:8080/gson.provider/v1/resources

• get Resource by Id http://localhost:8080/gson.provider/v1/resources/b1e581bf-8265-480c-a460-50c860df15be

Links

• Blog Entry @Lanora: http://lanora.io/2014/11/gson-jersey-provider/
• Eclipsesource by Moritz Post: http://eclipsesource.com/blogs/2012/11/02/integrating-gson-into-a-jax-rs-based-application/

Stackoverflow

• Stackoverflow #1: http://stackoverflow.com/a/9516224/1581725
• Stackoverflow #2: http://stackoverflow.com/a/29551143/1581725
• Stackoverflow #3: http://stackoverflow.com/a/29731719/1581725
• Stackoverflow #4: http://stackoverflow.com/a/26829444/1581725
• Stackoverflow #5: http://stackoverflow.com/a/29551143/1581725