JAX-RS and JSON-P integration

Abhishek GuptaOctober 16th, 2015Last Updated: October 15th, 2015

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This short post talks about support for JSON-P in JAX-RS 2.0

JSON-P …?

The JSON Processing API (JSON-P) was introduced in Java EE 7. It provides a standard API to work with JSON data and is quite similar to its XML counterpart – JAXP. JSON-B (JSON Binding) API is in the works for Java EE 8.

Support for JSON-P in JAX-RS 2.0

JAX-RS 2.0 (also a part of Java EE 7) has out-of-the-box support for JSON-P artifacts like JsonObject, JsonArray and JsonStructure i.e. every JAX-RS 2.0 compliant implementation will provide built in Entity Providers for these objects, making it seamless and easy to exchange JSON data in JAX-RS applications

Some examples

Sending JSON array from your JAX-RS resource methods:

@GET
public JsonArray buildJsonArray(){
  return Json.createArrayBuilder().add("jsonp").add("jaxrs").build();
}

Here is another example of how you can accept a JSON payload from the client

@POST
public void acceptJsonObject(JsonObject payload){
  System.out.println("theoad -- "+ payload.toString());
}

These are pretty simple examples, but I hope you get the idea….

Few things to be noted

No need to write custom MessageBodyReader or MessageBodyWriter implementations. As mentioned previously, the JAX-RS implementation does it for you for free !
This feature is not the same as being able to use JAXB annotations on POJOs and exchange JSON versions of the payload (by specifying the application/xml media type). This is not a standard feature yet, although I have experimented with this and observed that GlassFish 4.1 (Jersey) and Wildfly 8.x (RESTEasy) support this by default