Combine Netty and Spring MVC

Question

How can I configure Netty in Spring MVC. When and where should I start the Netty tcp server? Should I init netty once the Spring starts? Could someone show me an example such as the Spring configuration xml file or something eles? Thanks!

Answer 1

It really depends what you are using Netty for. Assuming you are using it as an embedded HTTP server running on a separate port, you could simply initialise it within a Spring bean. I've achieved this in the past using a useful Netty/Atmosphere wrapper called Nettosphere:

@Service
public class NettyServer implements ServletContextAware {

    private ServletContext servletContext;

    private Nettosphere server;

    @Autowired
    private MyStatusHandler statusHandler;

    @PostConstruct
    public void initialiseNettyServer() {
            String rootPath = servletContext.getContextPath() + "/api";

            server = new Nettosphere.Builder().config(
                    new Config.Builder()
                            .host(SERVER_HOST)
                            .port(SERVER_PORT)
                            .resource(rootPath + "/status", statusHandler)
                            .build())
                     .build();
            server.start();
    }

    @PreDestroy
    public void shutdownNettyServer() {
            server.stop();
    }

}

This assumes the annotation-based configuration in Spring, you can easily achieve the same result using XML as explained in Jonathan's answer.

Of course, you may prefer to use Netty directly, in which case the same principle applies, but you will need to dig into the Netty user guide a bit to bootstrap the server correctly.

Answer 2

Just create a bean with start and stop methods that are responsible for starting up and shutting down the Netty server and then register the bean in the context with appropriate init and destroy hooks, e.g.:

<bean id="myNettyServer" class="x.y.z.MyNettyServer" init-method="start" destroy-method="shutdown"/>

Or alternatively use @PostConstruct and @PreDestroy annotations if you don't want to use XML configuration.