Declare the following dependency in your project:

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

To enable Jackson support, first create and register a JacksonSupport instance with a Routing.Builder. JacksonSupport is a Service, so it will install its own Handler that will provide serialization and deserialization services using Jackson.

final JacksonSupport jacksonSupport = JacksonSupport.create(); 
final Routing.Builder routingBuilder = Routing.builder();
routingBuilder.register(jacksonSupport); 

• Create a JacksonSupport instance. This instance may be reused freely.
• Register that JacksonSupport 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 by Jackson.

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"}