Question

我有一个应用程序，客户端可以接收SseEmitter， SseEmitter会将jms消息中继到客户端。

客户端关闭连接（关闭浏览器）时出现问题。 IOException将引发以下无法捕获的异常：

2019-01-24 12:33:59.163 ERROR 26516 --- [nio-8080-exec-6] o.a.catalina.connector.CoyoteAdapter     : Exception while processing an asynchronous request

java.lang.IllegalStateException: Calling [asyncError()] is not valid for a request with Async state [MUST_DISPATCH]
    at org.apache.coyote.AsyncStateMachine.asyncError(AsyncStateMachine.java:440) ~[tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.coyote.AbstractProcessor.action(AbstractProcessor.java:512) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.coyote.Request.action(Request.java:430) ~[tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.catalina.core.AsyncContextImpl.setErrorState(AsyncContextImpl.java:382) ~[tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.catalina.connector.CoyoteAdapter.asyncDispatch(CoyoteAdapter.java:239) ~[tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.coyote.AbstractProcessor.dispatch(AbstractProcessor.java:241) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:53) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1417) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_162]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_162]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.14.jar:9.0.14]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_162]

捕获IOException不会阻止抛出此异常。我已经实现了一种解决方法，即客户端在其中发送请求以从要发送事件的发射器集合中删除其发射器。

但是，如果客户端/浏览器崩溃，此异常仍将引发。

   @Scheduled(fixedDelay = 2000L)
      public void sendEvent()  {
           TextMessage message = null;
           try {
               message = messageBlockingQueue.take();
           } catch (InterruptedException e) {
               e.printStackTrace();
           }
           for(SseEmitter sseEmitter:emitterMap.values()) {
               TextMessage finalMessage = message;
                   try {
                       sseEmitter.send(finalMessage.getText());
                   }  catch (IOException e) {
                       sseEmitter.completeWithError(e);
                   } catch (JMSException e) {
                       e.printStackTrace();
                   }
            }
        }

端点：

@CrossOrigin(allowCredentials = "true")
@RequestMapping(value = "/event", method = RequestMethod.GET)
public SseEmitter getEvent(HttpServletRequest request){
    HttpSession session = request.getSession();
    if(eventService.getEmitterMap().containsKey(session)){
        System.out.println("existing sub found:"+session.getId());
        return eventService.getEmitterMap().get(session);
    }else{
        final SseEmitter emitter = new SseEmitter(84000000000L);
        eventService.register(session,emitter);
        System.out.println("created new sub:"+session.getId());
        return emitter;
    }
}

Answer 1

经过进一步研究，可以将此异常归咎于tomcat中的错误。

https://github.com/spring-projects/spring-boot/issues/15057

要解决此问题，我已经从tomcat切换到了码头。

已发送事件IOException，导致无法捕获的IllegalStateException

1 个答案: