Declare the following dependency in your project:

<dependency>
    <groupId>io.helidon.media.jsonb</groupId>
    <artifactId>helidon-media-jsonb-server</artifactId>
</dependency>

To enable JSON-B support, first create and register a JsonBindingSupport instance with a Routing.Builder. JsonBindingSupport is a Service, so it will install its own Handler that will provide serialization and deserialization services using Yasson, an implementation of the JSON-B specification.

final JsonBindingSupport jsonBindingSupport = JsonBindingSupport.create(); 
final Routing.Builder routingBuilder = Routing.builder();
routingBuilder.register(jsonBindingSupport); 

• Create a JsonBindingSupport instance. This instance may be reused freely.
• Register that JsonBindingSupport instance to enable automatic deserialization of Java objects from and serialization of Java objects to JSON.

Now that automatic JSON serialization and deserialization facilities have been set up, you can register a Handler that works with Java objects instead of raw JSON. Deserialization from and serialization to JSON will be handled according to the JSON-B specification.

Suppose you have a Person class that looks like this:

public class Person {

    private String name;

    public Person() {
        super();
    }

    public String getName() {
        return this.name;
    }

    public void setName(final String name) {
        this.name = name;
    }
}

Then you can set up a Handler like this:

final Routing routing =
    routingBuilder.post("/echo", 
                        Handler.create(Person.class, 
                                       (req, res, person) -> res.send(person)))) 
    .build();

• Set up a route for POST requests using the Routing.Builder#post(String, Handler…​) method
• Use the Handler#create(Class, Handler.EntityHandler) method to install a Handler.EntityHandler that works with Person instances.
• This Handler.EntityHandler consumes a Person instance (person) and simply echoes it back. Note that there is no working with raw JSON here.

curl --noproxy '*' -X POST -H "Content-Type: application/json" \
    http://localhost:8080/echo -d '{"name":"Joe"}'
{"name":"Joe"}