In the previous examples, we exchanged messages only of type string. Sometimes, we may need to transfer more complex objects to the client, a Movie instance, for example, holding information such as the movie title, actors, and so on. From a RESTful background, the most popular solution is to convert the object to a JSON string. Rather than doing this manually before using the sendText(String) method, we can define a custom encode that automatically converts the object to the desired format.
Let's look at the following example:
@ServerEndpoint(value = "/movie/{movieId}",
encoders = {MovieEncoder.class})
public class MoviesEndpoint{
public void onOpen(Session session, EndpointConfig endpointConfig) {
Movie movie = new Movie();
try {
// fill with some data
session.getBasicRemote().sendObject(movie);
} catch (IOException | EncodeException ex) {
ex.printStackTrace();
}
} ...