tomcat7 - Tomcat 错误 : java. lang.IllegalStateException:调用 [asyncPostProcess()] 对具有异步状态 [STARTED] 的请求无效

Question

试图让这个简单的演示在 tomcat 7.0.37 上运行:
https://github.com/cometd/cometd-tutorials/tree/master/client-hello

我更改了 web.xml 以支持异步调用(cometD 用于长轮询)。

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns="http://java.sun.com/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
     version="3.0">

<servlet>
    <servlet-name>cometd</servlet-name>
    <servlet-class>org.cometd.annotation.AnnotationCometdServlet</servlet-class>
    <init-param>
        <param-name>transports</param-name>
        <param-value>org.cometd.websocket.server.WebSocketTransport</param-value>
    </init-param>
    <init-param>
        <param-name>services</param-name>
        <param-value>org.cometd.tutorials.ClientHelloService</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
    <async-supported>true</async-supported>
</servlet>
<servlet-mapping>
    <servlet-name>cometd</servlet-name>
    <url-pattern>/cometd/*</url-pattern>
</servlet-mapping>

<filter>
    <filter-name>cross-origin</filter-name>
    <filter-class>org.eclipse.jetty.servlets.CrossOriginFilter</filter-class>
    <async-supported>true</async-supported>
</filter>
<filter-mapping>
    <filter-name>cross-origin</filter-name>
    <url-pattern>/cometd/*</url-pattern>
</filter-mapping>

<filter>
    <filter-name>continuation</filter-name>
    <filter-class>org.eclipse.jetty.continuation.ContinuationFilter</filter-class>
    <async-supported>true</async-supported>
</filter>
<filter-mapping>
    <filter-name>continuation</filter-name>
    <url-pattern>/cometd/*</url-pattern>
</filter-mapping>

</web-app>

如果我按下按钮向服务器发送一些东西，我会收到以下错误:

java.lang.IllegalStateException: Calling [asyncPostProcess()] is not valid for a request with Async state [STARTED]
at org.apache.coyote.AsyncStateMachine.asyncPostProcess(AsyncStateMachine.java:204)
at org.apache.coyote.AbstractProcessor.asyncPostProcess(AbstractProcessor.java:116)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:593)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1686)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)

也许有人可以为这个堆栈带来光明？

Answer 1

确保在所有过滤器上都设置为 true。见 http://cometd.org/node/106

The async-supported element should be specified for the CometD servlet and for all filters that may be executed before the CometD servlet such as the CrossOriginFilter.

我遇到这个问题是因为我有一个新添加的过滤器，它与缺少此标签的 Cometd 无关。添加标签解决了问题。