java - 调用@Stateless bean 的@Asynchronous 方法时出现ContextNotActiveException

Question

我在异步 Servlet 中注入(inject)一个 @Stateless bean 并从 Serrvlet 调用 @Asynchronous 方法。在 jboss 的服务器日志中，我看不到任何异常，但是在启动 Java Mission Control 和 Flight Recorder 时，只要 Servlet 调用 @Asyncrhonous，我就可以看到 ContextNotActiveExcetion 方法。

服务小程序::

@WebServlet(urlPatterns = { "/asyncservice" }, asyncSupported = true)
public class AsyncServiceServlet extends HttpServlet {

@Inject
private Service service;

protected void doPost(final HttpServletRequest request, final HttpServletResponse response)
        throws ServletException, IOException {
    final AsyncContext asyncContext = request.startAsync(request, response);
    asyncContext.start(new Runnable() {
        @Override
        public void run() {
            try {
                service.service(asyncContext);
            } catch (ContextNotActiveException | IOException e) {
                e.printStackTrace();
            }
        });
    }

服务等级::

@Stateless
public class Service {

@Asynchronous
public void service(final AsyncContext asyncContext) throws IOException {
    HttpServletResponse res = (HttpServletResponse) asyncContext.getResponse();
    res.setStatus(200);
    asyncContext.complete();
     }
}

我可以在飞行记录器中看到的堆栈跟踪::

      java.lang.Throwable.<init>()  4
      java.lang.Exception.<init>()  4
      java.lang.RuntimeException.<init>()   4
      javax.enterprise.context.ContextException.<init>()    4
      javax.enterprise.context.ContextNotActiveException.<init>()   4
      org.jboss.weld.context.ContextNotActiveException.<init>(Enum,Object[])    4
      org.jboss.weld.manager.BeanManagerImpl.getContext(Class)  4
      org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(InterceptorContext)  4
     org.jboss.invocation.InterceptorContext.proceed()  4
        org.jboss.invocation.InitialInterceptor.processInvocation(InterceptorContext)   4
   org.jboss.invocation.InterceptorContext.proceed()    4
     org.jboss.invocation.ChainedInterceptor.processInvocation(InterceptorContext)  4
 org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(InterceptorContext)    4
    org.jboss.invocation.InterceptorContext.proceed()   4
      org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(InterceptorContext)  4
  org.jboss.invocation.InterceptorContext.proceed() 4
    org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(InterceptorContext,TransactionManager,EJBComponent) 4
    org.jboss.as.ejb3.tx.CMTTxInterceptor.required(InterceptorContext,EJBComponent,int) 4
  org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(InterceptorContext)

我已经看了很多帖子，但问题仍然存在，请帮助我。

Answer 1

AsyncContext.start 的 javadoc:

Registers the given AsyncListener with the most recent asynchronous cycle that was started by a call to one of the ServletRequest.startAsync() methods. The given AsyncListener will receive an AsyncEvent when the asynchronous cycle completes successfully, times out, or results in an error.

暗示到这个时候调用

service.service(asyncContext);

已创建，httpservletrequest“上下文”可能不可用，甚至可能已提交请求，导致 CDI 无法确定您的服务使用的任何“@RequestScoped”bean。

请注意，AsyncContext.start 会注册一个 onEvent，以便在异步调用完成或出错时调用，而不是在异步调用开始时调用。

您可能希望在调用 AsyncContext.start 之前添加要调用的监听器