@Bean
public HandlerMapping webSocketHandlerMapping() {
    Map<String, WebSocketHandler> map = new HashMap<>();
    map.put("/event-emitter", webSocketHandler);

    SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping();
    handlerMapping.setOrder(1);
    handlerMapping.setUrlMap(map);
    return handlerMapping;
}

@Component
public class ReactiveWebSocketHandler implements WebSocketHandler {
    
    // private fields ...

    @Override
    public Mono<Void> handle(WebSocketSession webSocketSession) {
        return webSocketSession.send(intervalFlux
          .map(webSocketSession::textMessage))
          .and(webSocketSession.receive()
            .map(WebSocketMessage::getPayloadAsText)
            .log());
    }
}

public class ReactiveJavaClientWebSocket {
 
    public static void main(String[] args) throws InterruptedException {
 
        WebSocketClient client = new ReactorNettyWebSocketClient();
        client.execute(
          URI.create("ws://localhost:8080/event-emitter"), 
          session -> session.send(
            Mono.just(session.textMessage("event-spring-reactive-client-websocket")))
            .thenMany(session.receive()
              .map(WebSocketMessage::getPayloadAsText)
              .log())
            .then())
            .block(Duration.ofSeconds(10L));
    }
}