使用标准 JSR356 WebSocket 客户端的连接超时

Question

我有一个连接到远程 websocket 服务器的 Java 应用程序。作为客户，我使用的是标准 Java EE JSR356 WebSocket API:

javax.websocket.WebSocketContainer.connectToServer(...)

但是，我还没有找到使用此 API 指定连接超时的方法。当我调用 connectToServer(...) 方法时，它会阻塞直到建立连接（这可能永远不会发生）。

有没有办法使用标准 API 指定连接超时？如果没有，是否有任何解决方法？

Answer 1

不幸的是，JSR 356 - WebSocket API for Java. You will need to use implementation feature, such as HANDSHAKE_TIMEOUT in Tyrus（参考实现）没有公开这一点。其他实现很可能会有类似的东西。

WEBSOCKET_SPEC, so you can add one if you want (I was able to find only issue which is mentioning SSL properties - WEBSOCKET_SPEC-210 中似乎还没有关于此的工单。

Answer 2

我自己刚刚开始工作。如果您通过 Future 构造调用 connectToServer，则可以在 get() 方法中使用超时。

您需要一个线程池：

private final ExecutorService pool = Executors.newFixedThreadPool(10);

函数如下：

private Future<Session> asyncConnectToServer(Object annotatedEndpointInstance, URI uri) {
        return pool.submit(new Callable<Session>() {
            @Override
            public Session call() throws Exception {
                try {
                    WebSocketContainer container = ContainerProvider.getWebSocketContainer();
                    return(container.connectToServer(annotatedEndpointInstance, uri));
                } catch (DeploymentException | IOException | IllegalStateException  e) {
                    //throw new RuntimeException(e);
                    return(null);
                }
            }
        });
    }

你是这样称呼它的：

 public webSocketClientEndpoint(URI endpointURI, long timeout) {

        final Future<Session> futureSes = asyncConnectToServer(this, endpointURI);

        try {            
            Session ses = futureSes.get(timeout, TimeUnit.MILLISECONDS);
        } catch(InterruptedException | ExecutionException | TimeoutException  e) {
            System.out.println("Time out...");
        }
    }

参考： https://dzone.com/articles/javautilconcurrentfuture

https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Future.html#get(long,%20java.util.concurrent.TimeUnit)

Answer 3

您可以简单地覆盖 WsWebSocketContainer 中的 connectToServer 方法

public class WsWebSocketContainer2 extends WsWebSocketContainer {

    @Override
    public Session connectToServer(Object pojo, URI path) throws DeploymentException {
        ClientEndpoint annotation = pojo.getClass().getAnnotation(ClientEndpoint.class);
        if (annotation == null) {
            throw new DeploymentException("wsWebSocketContainer.missingAnnotation");
        }

        Endpoint ep = new PojoEndpointClient(pojo, Arrays.asList(annotation.decoders()));

        Class<? extends ClientEndpointConfig.Configurator> configuratorClazz = annotation.configurator();

        ClientEndpointConfig.Configurator configurator = null;
        if (!ClientEndpointConfig.Configurator.class.equals(configuratorClazz)) {
            try {
                configurator = configuratorClazz.getConstructor().newInstance();
            } catch (ReflectiveOperationException e) {
                throw new DeploymentException("wsWebSocketContainer.defaultConfiguratorFail", e);
            }
        }

        ClientEndpointConfig.Builder builder = ClientEndpointConfig.Builder.create();
        // Avoid NPE when using RI API JAR - see BZ 56343
        if (configurator != null) {
            builder.configurator(configurator);
        }
        ClientEndpointConfig config = builder.decoders(Arrays.asList(annotation.decoders())).encoders(Arrays.asList(annotation.encoders()))
                .preferredSubprotocols(Arrays.asList(annotation.subprotocols())).build();
        Map<String, Object> userProperties = config.getUserProperties();
        userProperties.put(Constants.IO_TIMEOUT_MS_PROPERTY, 999999);
        return connectToServer(ep, config, path);
    }
}

使用标准 JSR356 WebSocket 客户端的连接超时

Connection timeout using standard JSR356 WebSocket client

connection

timeout

websocket

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