为 Spring Boot 驱动的 Vaadin 应用程序启用服务器推送不起作用

Question

在我们当前的项目中，我们希望在 Spring Boot 驱动的 Vaadin 应用程序中使用 server-push。

我们按照 wiki 文章 https://vaadin.com/book/vaadin7/-/page/advanced.push.html 中的说明进行操作（向 pom.xml 添加了 vaadin-push 依赖项，向 out UI 类添加了 @Push 注释，没有在 web.xml 文件中设置异步支持，因为它没有在这种情况下存在）并收到以下错误消息：

2014-06-17 14:32:43,340 [http-nio-8080-exec-3] WARN  org.atmosphere.cpr.AtmosphereFramework - SessionSupport error. Make sure you define org.atmosphere.cpr.SessionSupport as a listener in web.xml instead
2014-06-17 14:32:44,981 [http-nio-8080-exec-3] WARN  org.atmosphere.cpr.DefaultAsyncSupportResolver - Found multiple containers, please specify which one to use: org.atmosphere.container.Tomcat7CometSupport, org.atmosphere.container.TomcatCometSupport,  until you do, Atmosphere will use:class org.atmosphere.container.Tomcat7CometSupport
2014-06-17 14:32:45,001 [http-nio-8080-exec-3] WARN  org.atmosphere.cpr.AtmosphereFramework - Failed using comet support: org.atmosphere.container.Tomcat7CometSupport, error: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar Is the NIO or APR Connector enabled?
2014-06-17 14:32:45,005 [http-nio-8080-exec-3] ERROR org.atmosphere.cpr.AtmosphereFramework - If you have more than one Connector enabled, make sure they both use the same protocol, e.g NIO/APR or HTTP for all. If not, org.atmosphere.container.BlockingIOCometSupport will be used and cannot be changed.
java.lang.IllegalStateException: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar
    at org.atmosphere.container.Tomcat7CometSupport.<clinit>(Tomcat7CometSupport.java:56) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
    (...)
2014-06-17 14:32:45,006 [http-nio-8080-exec-3] WARN  org.atmosphere.cpr.AtmosphereFramework - Using org.atmosphere.container.BlockingIOCometSupport

2014-06-17 14:32:58,684 [http-nio-8080-exec-1] ERROR com.vaadin.server.DefaultErrorHandler - 
java.lang.IllegalStateException: Cannot suspend a response longer than the session timeout. Increase the value of session-timeout in web.xml
    at org.atmosphere.cpr.AtmosphereResourceImpl.suspend(AtmosphereResourceImpl.java:314) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
    (...)

在阅读 stackoverflow 线程 Getting rid of web.xml in Vaadin 7 with VaadinServlet 后，我们在 UI 类中添加了一个静态 servlet

@WebServlet(asyncSupported = true)
public static class Servlet extends VaadinServlet {
}

并得到相同的错误消息：

2014-06-17 14:33:52,928 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - SessionSupport error. Make sure you define org.atmosphere.cpr.SessionSupport as a listener in web.xml instead
2014-06-17 14:33:54,557 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.DefaultAsyncSupportResolver - Found multiple containers, please specify which one to use: org.atmosphere.container.Tomcat7CometSupport, org.atmosphere.container.TomcatCometSupport,  until you do, Atmosphere will use:class org.atmosphere.container.Tomcat7CometSupport
2014-06-17 14:33:54,577 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - Failed using comet support: org.atmosphere.container.Tomcat7CometSupport, error: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar Is the NIO or APR Connector enabled?
2014-06-17 14:33:54,581 [http-nio-8080-exec-1] ERROR org.atmosphere.cpr.AtmosphereFramework - If you have more than one Connector enabled, make sure they both use the same protocol, e.g NIO/APR or HTTP for all. If not, org.atmosphere.container.BlockingIOCometSupport will be used and cannot be changed.
java.lang.IllegalStateException: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar
    at org.atmosphere.container.Tomcat7CometSupport.<clinit>(Tomcat7CometSupport.java:56) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
   (...)
2014-06-17 14:33:54,582 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - Using org.atmosphere.container.BlockingIOCometSupport

2014-06-17 14:34:07,338 [http-nio-8080-exec-3] ERROR com.vaadin.server.DefaultErrorHandler - 
java.lang.IllegalStateException: Cannot suspend a response longer than the session timeout. Increase the value of session-timeout in web.xml
    at org.atmosphere.cpr.AtmosphereResourceImpl.suspend(AtmosphereResourceImpl.java:314) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
    (...)

为会话超时添加一个参数也没有改变任何东西：

@WebServlet(asyncSupported = true, initParams = { @WebInitParam(name = "session-timeout", value = "120") })
public static class Servlet extends VaadinServlet {
}

2014-06-17 14:36:18,636 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - SessionSupport error. Make sure you define org.atmosphere.cpr.SessionSupport as a listener in web.xml instead
2014-06-17 14:36:20,284 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.DefaultAsyncSupportResolver - Found multiple containers, please specify which one to use: org.atmosphere.container.Tomcat7CometSupport, org.atmosphere.container.TomcatCometSupport,  until you do, Atmosphere will use:class org.atmosphere.container.Tomcat7CometSupport
2014-06-17 14:36:20,303 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - Failed using comet support: org.atmosphere.container.Tomcat7CometSupport, error: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar Is the NIO or APR Connector enabled?
2014-06-17 14:36:20,307 [http-nio-8080-exec-1] ERROR org.atmosphere.cpr.AtmosphereFramework - If you have more than one Connector enabled, make sure they both use the same protocol, e.g NIO/APR or HTTP for all. If not, org.atmosphere.container.BlockingIOCometSupport will be used and cannot be changed.
java.lang.IllegalStateException: Tomcat failed to detect this is a Comet application because context.xml is missing or the Http11NioProtocol Connector is not enabled.You must use the atmosphere-native-runtime dependency in order to use native Comet Support
If that's not the case, you can also remove META-INF/context.xml and WEB-INF/lib/atmosphere-compat-tomcat7.jar
    at org.atmosphere.container.Tomcat7CometSupport.<clinit>(Tomcat7CometSupport.java:56) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
    (...)
2014-06-17 14:36:20,308 [http-nio-8080-exec-1] WARN  org.atmosphere.cpr.AtmosphereFramework - Using org.atmosphere.container.BlockingIOCometSupport

2014-06-17 14:36:44,341 [http-nio-8080-exec-9] ERROR com.vaadin.server.DefaultErrorHandler - 
java.lang.IllegalStateException: Cannot suspend a response longer than the session timeout. Increase the value of session-timeout in web.xml
    at org.atmosphere.cpr.AtmosphereResourceImpl.suspend(AtmosphereResourceImpl.java:314) ~[atmosphere-runtime-2.1.2.vaadin2.jar:2.1.2.vaadin2]
    (...)

您对解决方案有什么想法吗？

Answer 1

目前，Spring + Vaadin 仅在您未将 WEBSOCKET 设置为传输模式时才有效。尝试将其更改为长轮询或流式传输：

@Push(transport = Transport.LONG_POLLING)

就我个人而言，我仍然为 Web 应用程序使用旧的 xml 配置。这是 Vaadin 7 的推送配置的一部分。

 <!-- Vaadin context -->
<servlet>
    <servlet-name>ISM Application</servlet-name>
    <servlet-class>org.vaadin.spring.servlet.SpringAwareVaadinServlet</servlet-class>
    <init-param>
        <param-name>closeIdleSessions</param-name>
        <param-value>true</param-value>
    </init-param>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:ism-web.xml</param-value>
    </init-param>
    <!-- Vaadin 7.1 @Push -->
    <init-param>
        <param-name>org.atmosphere.useWebSocketAndServlet3</param-name>
        <param-value>true</param-value>
    </init-param>
    <async-supported>true</async-supported>
</servlet>

Answer 2

观看以下 Vaadin 网络研讨会后，我从服务器推送切换到轮询，这解决了我的问题：

• http://www.youtube.com/watch?v=GOKX-bGmi0k
• http://www.youtube.com/watch?v=ZUshNi_4Gqc

以下 wiki 描述了如何使用轮询：

https://vaadin.com/wiki/-/wiki/Main/Using+polling