How to configure Jackson in Wildfly?

Question

I've got a Session Bean with the following method:

@POST
@Consumes("application/x-www-form-urlencoded")
@Path("/calculate")
@Produces("application/json")
public CalculationResult calculate(@FormParam("childProfile") String childProfile,
        @FormParam("parentProfile") String parentProfile) {
...
}

The returned CalculationResult cannot be mapped to JSON and the following exception occurs:

Caused by: com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class com.test.UniqueName and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS)...

How can I configure Jackson and its SerializationFeature in Wildfly?

Answer 1

Wildfly 9

pom.xml

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jackson2-provider</artifactId>
    <version>3.0.8.Final</version>
    <scope>provided</scope>
</dependency>

Java class

@com.fasterxml.jackson.annotation.JsonIgnoreProperties(ignoreUnknown = true)
public class SomePojo implements Serializable {
}

Answer 2

"How can I configure Jackson and its SerializationFeature in Wildfly?"

You don't need to configure it in Wildfly, you can configure it in the JAX-RS applciation. Just use a ContextResolver to configure the ObjectMapper (see more here). Something like

@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {

    private final ObjectMapper mapper;

    public ObjectMapperContextResolver() {
        mapper = new ObjectMapper();
        mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return mapper;
    }

}

If you don't already have the Jackson dependency, you need that, just as a compile-time dependency

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jackson-provider</artifactId>
    <version>3.0.8.Final</version>
    <scope>provided</scope>
</dependency>

If you are using scanning to discover your resource classes and provider classes, the ContextResolver should be discovered automatically. If you explicitly registering all your resource and providers, then you'll need to register this one also. It should be registered as a singleton.

---

UPDATE

As @KozProv mentions in a comment, it should actually be resteasy-jackson2-provider as the artifactId for the Maven dependency. -jackson- uses the older org.codehaus (Jackson 1.x), while the -jackson2- uses the new com.fasterxml (Jackson 2.x). Wildfly by default uses The Jackson 2 version.