Serialize javax.ws.rs Entity to json

You can't test like this. What you are doing here

Response response = Response.status(Response.Status.OK)                            .entity(entity)                            .type(MediaType.APPLICATION_JSON).build();

is building an outbound response. In the JAX-RS framework, after we send out a response, e.g.

@GET@Produced(MediaType.APPLICATION_JSON)public Response getResponse() {    ...    return Response.status(Response.Status.OK)                    .entity(entity)                    .type(MediaType.APPLICATION_JSON).build();}

it still needs to through a MessageBodyWriter for the serialization to JSON.

• Read more about Entity Providers

That being said, Jersey has a Test Framework, we can use to test our resource methods. You can find all the official examples at the Github

A sample (with a few alterations):

These are the minimum required Maven dependencies

<dependencies>    <dependency>        <groupId>org.glassfish.jersey.test-framework</groupId>        <artifactId>jersey-test-framework-core</artifactId>        <version>2.13</version>    </dependency>    <dependency>        <groupId>org.glassfish.jersey.test-framework.providers</groupId>        <artifactId>jersey-test-framework-provider-grizzly2</artifactId>        <version>2.13</version>    </dependency>    <dependency>        <groupId>org.glassfish.jersey.media</groupId>        <artifactId>jersey-media-json-jackson</artifactId>        <version>2.13</version>    </dependency></dependencies>

Test class

public class TestJSONResource extends JerseyTest {    @Override    protected TestContainerFactory getTestContainerFactory() {        return new GrizzlyTestContainerFactory();    }    @Path("test")    public static class TestResource {        @GET        @Produces(MediaType.APPLICATION_JSON)        public Response getJson() {            Map<String, String> entity = Maps.newHashMap();            entity.put("foo", "bar");            Response response = Response.status(Response.Status.OK)                    .entity(entity)                    .type(MediaType.APPLICATION_JSON).build();            return response;        }    }    @Override    protected DeploymentContext configureDeployment() {        return DeploymentContext.builder(new ResourceConfig(TestResource.class))                .contextPath("context1/context2")                .build();    }    @Test    public void testGet() {        final WebTarget target = target("test");        final String s = target.request().get(String.class);        System.out.println(s);    }}

jersey-media-json-jackson provides the MessageBodyWriter and MessageBodyReader for processing JSON, which is implicitly registered for us.