Jackson Support

Maven Coordinates

To enable Jackson Support add the following dependency to your project’s pom.xml (see Managing Dependencies).

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

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Jackson Support

The WebServer supports Jackson. When this support is enabled, Java objects will be serialized to and deserialized from JSON automatically using Jackson.

Usage

To enable Jackson support, first create and register a JacksonSupport instance with a WebServer.Builder.

Registration of the JacksonSupport via WebServer

JacksonSupport jacksonSupport = JacksonSupport.create(); 
WebServer webServer = WebServer.builder()
    .addMediaSupport(jacksonSupport) 
    .build();

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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:

Hypothetical Person class

public class Person {

    private String name;

    public Person() {
        super();
    }

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

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

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Then you can set up a Handler like this:

A Handler that works with Java objects instead of raw JSON

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

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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.

Example of posting JSON to the /echo endpoint

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

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