将Spring Websocket转换为Jetty Websocket

Question

我开始将我现有的Jetty9应用程序webapp迁移到Spring Boot上，但我似乎不知道如何使用Jetty WebSocketHandler，而不是Spring WebSocketHandler和WebSocketSession。

我可以在我的Application.java中正确地设置Spring WebSocketHandler，我在Spring Framework文档中找到了JettyWebSocketHandlerAdaptor和JettyWebSocketSession类，但我还没有找到如何使用它或任何好的示例。

http://docs.spring.io/autorepo/docs/spring-framework/4.1.9.RELEASE/javadoc-api/org/springframework/web/socket/adapter/jetty/JettyWebSocketHandlerAdapter.html

如何将WebSocketHandler交给Jetty？因为JettyWebSocketAdapter不是从Object派生的，所以我一直在尝试注册一个Spring WebSocketHandler，然后让它的所有方法都传递给一个JettyWebSocketHandler。我这么做是不是太傻了：

Application.java

@EnableWebSocket
@SpringBootApplication
public class Application extends SpringBootServletInitializer implements WebSocketConfigurer {



    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        SpringWSHandler springPlease = new SpringWSHandler();


        registry.addHandler(springPlease, "/websocket").setHandshakeHandler(handshaker());
    }

    @Bean
    public DefaultHandshakeHandler handshaker()
    {
        WebSocketPolicy policy = new WebSocketPolicy(WebSocketBehavior.SERVER);
        policy.setInputBufferSize(8192);
        policy.setIdleTimeout(600000);

        return new DefaultHandshakeHandler(new JettyRequestUpgradeStrategy(new WebSocketServerFactory(policy)));
    }


    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);

    }
}

Spring WebSocketHandler

@Component
public class SpringWSHandler implements WebSocketHandler {

    private JettyHandler jettyHandler;
    private JettyWebSocketSession jettySession;

    private static Logger logger = LoggerFactory.getLogger(SpringWSHandler.class);



    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        logger.debug("Connection Established: " + session.getId());
        jettySession = new JettyWebSocketSession(session.getAttributes());
        jettyHandler = new JettyHandler(this, jettySession);
        jettyHandler.onOpen(jettySession.getNativeSession());

    }

    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
        logger.debug("Message from session: " + session.getId());
        jettyHandler.onMessage(message.getPayload().toString());

    }

    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        //TODO

    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        logger.debug("Closing the session: " + session.getId());
        jettyHandler.onClose(closeStatus.getCode(), "Closing Connection");
        session.close(closeStatus);
    }

    @Override
    public boolean supportsPartialMessages() {
        return true;
    }

}

它失败了，因为在我打开我的网页后，每当我试图使用它时，网页套接字连接似乎都会关闭。一旦我尝试使用jettyHandler的方法，连接就会关闭，异常是一个ExceptionWebSocketHandlerDecorator异常：

11:44:27.530 [qtp1014565006-19] ERROR o.s.w.s.h.ExceptionWebSocketHandlerDecorator - Unhandled error for ExceptionWebSocketHandlerDecorator [delegate=LoggingWebSocketHandlerDecorator [delegate=org.appcad.webserver.jetty.SpringWSHandler@5a7b309b]]
java.lang.NullPointerException: null

Answer 1

直接使用Spring的WebSocketHandler或Jetty的WebSocketHandler，不要尝试将它们混合在一起。

您不能以这种方式使用Jetty WebSocketHandler，因为它需要是Jetty LifeCycle层次结构的一部分，并且能够正常访问Jetty Server。

让一个合适的Jetty访问Spring层也是很困难的，因为Jetty和WebSocketHandler之间的LifeCycle不会像那样融合在一起。

也许您可以使用WebSocketUpgradeFilter和WebSocketCreator的自定义实现来初始化您的目标WebSocket，并在完成后访问Spring层。

您的自定义WebSocketCreator将在每次发生新的传入websocket升级时被调用。

Answer 2

我已经设法破解了一些暂时有效的东西，但我希望听到一个更好、更合适的方法来使用Jetty WebSockets和Spring Boot。

这允许我将消息从Spring传递到我的JettyWebSocketHandlerAdapter (JettyHandler)类，后者将消息传递给我的WebSocket WebSocket和相关的类。

Application.java中的WebSocketHandler设置

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {        
        SpringWSHandler springPlease = new SpringWSHandler();

        registry.addHandler(springPlease, "/websocket").setHandshakeHandler(factoryBean());
    }

    //Configure buffer size and timeouts
    @Bean
    public HandshakeHandler factoryBean()
    {
        WebSocketPolicy policy = new WebSocketPolicy(WebSocketBehavior.SERVER);
        policy.setInputBufferSize(8192);
        policy.setIdleTimeout(3600000);
        WebSocketServerFactory factory = new WebSocketServerFactory(policy);
        return new DefaultHandshakeHandler(new JettyRequestUpgradeStrategy(factory));
    }

SpringWSHandler.java

@Component
public class SpringWSHandler implements WebSocketHandler {

    private JettyHandler jettyHandler;
    private JettyWebSocketSession jettySession;

    private static Logger logger = LoggerFactory.getLogger(SpringWSHandler.class);



    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        //Application.java adapts WebSocket connections to Jetty 9 API when registering handlers with the Jetty handshaker
        //We can cast spring WebSocketSessions to JettyWebSocketSessions, and initialize the org.eclipse.jetty.websocket.api.Session with itself.
        jettySession = (JettyWebSocketSession) session;
        jettySession.initializeNativeSession(jettySession.getNativeSession());

        //Setup our custom handler and populate the router, which was magically created by Spring using our annotated classes in Router and its dependencies.       
        jettyHandler = new ClothoJettyHandler(this, jettySession);

        //Let the jetty web socket commence!
        jettyHandler.onOpen(jettySession.getNativeSession());

    }

    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
        logger.debug("Message from session: " + session.getId());
        jettyHandler.onMessage(message.getPayload().toString());

    }

    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        //TODO

    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        logger.debug("Closing the session: " + session.getId());
        jettyHandler.onClose(closeStatus.getCode(), "Closing Connection");
        session.close(closeStatus);
    }

    @Override
    public boolean supportsPartialMessages() {
        return true;
    }

}