JAX-RS and JSON-P Integration

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("the payload -- "+ 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

Further Reading

• Official JAX-RS specification document – nice and compact!
• Some of my previous posts on Java EE 7 and Java EE 8
• The Aquarium: From the Java EE Evangelism folks at Oracle

Cheers!