How to retrieve resource method's Annoations in MessageBodyWriter in Jersey?

jersey 2.21.

I have a resource file like below

……
@POST
@Path("/userReg")
@Produces("application/json;charset=UTF-8")
public JsonResp userReg(UserRegReq userRegReq) throws LoginNameExists {
    HttpHeaderUtils.parseHeaders(userRegReq, headers);

    //JsonResp is a custom java class.
    JsonResp result = new JsonResp();

    //will throw LoginNameExists
    User user = userManager.register(userRegReq.getLoginName(), userRegReq.getPassword());

    //success
    result.setResult(0);
result.setData(user.getId);

    return result;
}
……

To return the result to client, I implement a custom MessageBodyWriter like below

@Produces("application/json")
public class MyRespWriter implements MessageBodyWriter<JsonResp> {

    @Override
    public boolean isWriteable(Class<?> aClass, Type type, Annotation[] annotations, MediaType mediaType) {
        return type == JsonResp.class;
    }

    @Override
    public long getSize(JsonResp jsonResp, Class<?> aClass, Type type, Annotation[] annotations, MediaType mediaType) {
        return 0;
    }

    @Override
public void writeTo(JsonResp jsonResp, Class<?> aClass, Type type, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> multivaluedMap, OutputStream outputStream) throws IOException, WebApplicationException {
        //if these no exception in userReg(), 
        //the parameter annotations contains the annotations 
        //such as POST, Path, Produces;
        //but if there is an exception in userReg(), 
        //the parameter annotations contains none of POST, Path, Produces; 
        //So, is there any way to retrieve the original annotations all along?


        //JsonUtils is a custom java class.
        String data = JsonUtils.toJsonString(jsonResp);
        Writer osWriter = new OutputStreamWriter(outputStream, "UTF-8");
        osWriter.write(data);
        osWriter.flush();
    }
}

And to handle the exceptions, I implement a ExceptionMapper like this:

public class MyExceptionMapper implements ExceptionMapper<Exception> {

    public Response toResponse(Exception e) {

        JsonResp result = new JsonResp();

        //error
        result.setResult(-1);
        result.setErrMsg("System error.");

        return Response.ok(result, MediaType.APPLICATION_JSON_TYPE).status(Response.Status.OK).build();
    }
}

Now, if everything is ok and there’s no exception, the code execution router is userReg() -> MyRespWriter.writeTo(), the parameter "annotations" of MyRespWriter.writeTo() contains the correct annotations of method userReg(), such as POST, Path, Produces.

But if userReg() throws exception, the code execution router is userReg() -> MyExceptionMapper.toResponse() -> MyRespWriter.writeTo(), the parameter "annotations" of method MyRespWriter.writeTo() has none of the annotations of method userReg().

I want to know, is there any way that MyRespWriter.writeTo() can retrieve the original annotations all along?

You can inject ResourceInfo, then get the Method with ri.getResourceMethod(), then call method.getAnnotations() to get the annotations.

public class MyRespWriter implements MessageBodyWriter<JsonResp> {

    @Context
    ResourceInfo ri;

    ...

    Annotations[] annos = ri.getResourceMethod().getAnnotations();