我有一个部署到 JBoss 7.1.1.Final 的 Java EE 应用程序。该应用程序利用 JAX-RS 为客户端提供 REST 服务。其中一项服务保持客户端连接，直到通过 BlockingQueue 接收到响应对象。到目前为止，这似乎工作正常。但是，即使删除应用程序部署/关闭应用程序，连接也会保持打开状态。它甚至可以防止 JBoss 关闭。

所以我试图通过 @PreDestroy 回调中断等待线程来执行干净关闭。该服务如下所示:

@Path("/mypath")
@SessionScoped
public class MyResource implements Serializable {
  private static final long serialVersionUID = 1L;

  @Inject
  private EntityManager em;

  private Thread thread = null;

  @GET
  @Path("/{id:[0-9][0-9]*}")
  @Produces({
    MediaType.TEXT_PLAIN,
    MediaType.TEXT_XML
  })
  public Response getObjects(@PathParam("id") long id) {
    MyGroup group = this.em.find(MyGroup.class, id);
    if (group == null) {
      return Response.status(Status.NOT_FOUND)
          .entity("Group not found\n")
          .build();
    }

    if (group.isEmpty()) {
      return Response.status(Status.PRECONDITION_FAILED)
          .entity("Group is empty\n")
          .build();
    }

    BlockingQueue<?> queue = ... // Get queue for group

    this.thread = Thread.currentThread();
    try {
      MyObject object = queue.take();
    } catch (InterruptedException e) {
      return Response.noContent().build();
    }

    return Response.ok(object)
        .type(MediaType.TEXT_XML)
        .build();
  }

  @PreDestroy
  public void shutdown() {
    if (this.thread != null) {
      this.thread.interrupt();
    }
  }
}

它似乎可以工作，有点... 客户端收到了预期的响应。然而，JBoss 打印出这个异常:

13:38:44,489 ERROR [org.jboss.as.txn] JBAS010151: Unable to get transaction state: java.lang.IllegalStateException
    at org.jboss.msc.value.InjectedValue.getValue(InjectedValue.java:47)
    at org.jboss.as.txn.deployment.TransactionRollbackSetupAction.teardown(TransactionRollbackSetupAction.java:43)
    at org.jboss.as.web.ThreadSetupBindingListener.unbind(ThreadSetupBindingListener.java:61) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:195) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Thread.java:636) [rt.jar:1.6.0_18]

13:38:44,492 ERROR [org.apache.catalina.connector.CoyoteAdapter] An exception or error occurred in the container during the request processing: java.lang.RuntimeException: java.lang.IllegalStateException
    at org.jboss.as.web.ThreadSetupBindingListener.unbind(ThreadSetupBindingListener.java:67) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:195) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Thread.java:636) [rt.jar:1.6.0_18]
Caused by: java.lang.IllegalStateException
    at org.jboss.msc.value.InjectedValue.getValue(InjectedValue.java:47)
    at org.jboss.as.connector.deployers.processors.CachedConnectionManagerSetupProcessor$CachedConnectionManagerSetupAction.teardown(CachedConnectionManagerSetupProcessor.java:83)
    at org.jboss.as.web.ThreadSetupBindingListener.unbind(ThreadSetupBindingListener.java:61) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    ... 8 more

只是感觉不对。中断这种等待请求的正确方法是什么？

最佳答案

您正在中断容器创建的线程，因此容器无法自行完成线程。您可以使用状态变量来检查线程是否应该结束，而不是中断，例如(将其解释为伪代码):

while( ! stopped ) {
    MyObject object = queue.poll(25, TimeUnit.MILLISECONDS);

    return Response.ok(object)
        .type(MediaType.TEXT_XML)
        .build();
}

return Response.noContent().build();

并在 @PreDestroy 中将停止设置为 true。还有 AsyncResponse特征。您可以将所有打开的请求存储在一个列表中，然后在 @PreDestroy 中取消它们。

关于java - 如何正确中断 JAX-RS AJAX 请求，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14338097/