Java – Jersey didn’t see my messagebodyreader

I'm trying to use my own JSON messagebodyreader / messagebodywriter (because I didn't use @ xmlrootelement... Annotation on my domain class)

@Provider
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public final class MyGsonMessageBodyHandler implements MessageBodyWriter<Object>,MessageBodyReader<Object> {
...
}

Jersey uses this class as a messagebodywriter (because it stops at a breakpoint in the implemented method writeto) Hovewer doesn't see this class as a messagebodyreader (it still refuses to use my messagebodyreader even when I decompose this class into a separate implementation of messagebodyreader / messagebodywriter)

The test code is as follows (Jersey grizzly):

final Greeting greeting = resource.path("/greeting")
            .queryParam("name",name)
            .accept(MediaType.APPLICATION_JSON)
            .type(MediaType.APPLICATION_JSON)
            .get(Greeting.class);

I got the following error:

A message body reader for Java class test.Greeting,and Java type class test.Greeting,and MIME media type application/json was not found

I want to know what kind of magic is needed to write my own messagebodyreader?

Solution

After a while, I found the root cause of the problem My messagebodyreader / writer implementation is OK (I work normally with restlet), but if you use jerseytest, please don't forget to add messagebodyreader / writer to its clientconfig:

/**
 * Creates custom REST client config which is mandatory since we don't use any JSON providers.
 * @return Jersey Client Config with the required classes to read/write in(out)coming data.
 */
private static ClientConfig createClientConfig() {
    final ClientConfig config = new DefaultClientConfig();
    config.getClasses().add(GsonMessageBodyHandler.class);
    config.getClasses().add(GsonAwareContextResolver.class);
    return config;
}

/**
 * Public ctor
 * @throws com.sun.jersey.test.framework.spi.container.TestContainerException On error
 */
public MyRestExposuretest() throws TestContainerException {
    super(new WebAppDescriptor.Builder("my.rest.package")
            .clientConfig(createClientConfig())
            .contextPath("/")
            .build());
}

Otherwise, your client code will not be able to read / write to your POJO