【发布时间】：2017-07-11 22:38:50
【问题描述】：
环境：
- 在我的环境中，Kibana 4.5.2 在通过扩展 Jetty 的“ProxyServlet”类创建的“反向代理 servlet”后面运行。
- 这样做是为了可以使用 URL https://Jetty_Server_IP:8443/visual-analytics/proxy/... 访问 Kibana Web 界面。对此 URL 的请求被 Jetty 服务器中运行的反向代理拦截并重定向到 https://localhost:5601/... 即，到与 Jetty 服务器在同一台机器上运行的 Kibana 服务器。
- Kibana 服务器然后处理 Jetty 服务器转发的请求并将响应返回给 Web 浏览器。
- 注意： Jetty 在我的应用程序中以“嵌入式模式”运行。
问题：
“反向代理 servlet”映射到 URL“/visual-analytics/proxy/*”。
还有另一个“过滤器”映射到 URL“/visual-analytics/proxy/elasticsearch/.kibana/search/*”，其中使用了 ContinuationListener，如以下代码 sn-p 所示：
ContinuationSupport.getContinuation(myRequestWrapper).addContinuationListener(new ContinuationListener() {
@Override
public void onTimeout(Continuation continuation) {
logger.log(Level.WARNING, "Request timeout...");
}
@Override
public void onComplete(Continuation continuation) {
HttpServletResponse httpResponse = (HttpServletResponse)continuation.getServletResponse();
if (httpResponse.getStatus() == HttpServletResponse.SC_OK || httpResponse.getStatus() == HttpServletResponse.SC_CREATED ) {
//some business logic
}
}
});
chain.doFilter(myRequestWrapper, response);
上述 ContinuationListener 在 Jetty 版本 8.1.15.v20140411 上运行良好，并且正在调用侦听器的 onComplete() 方法。但是在将 Jetty 版本升级到 9.3.14.v20161028 后，ContinuationListener 不再工作，即，监听器的 onComplete() 方法和 onTimeout() 方法都没有被调用。
由于 ContinuationListener 不再工作，我将其替换为“javax.servlet.AsyncListener”实现，如以下代码 sn-p 所示：
AsyncContext asyncContext = myRequestWrapper.startAsync();
asyncContext.addListener(new AsyncListener() {
@Override
public void onTimeout(AsyncEvent event) throws IOException
{
logger.log(Level.WARNING, "Async timeout...");
}
@Override
public void onStartAsync(AsyncEvent event) throws IOException
{
logger.log(Level.INFO, "Async start...");
}
@Override
public void onError(AsyncEvent event) throws IOException
{
logger.log(Level.SEVERE, "Async error...");
}
@Override
public void onComplete(AsyncEvent event) throws IOException
{
HttpServletResponse httpResponse = (HttpServletResponse) event.getSuppliedResponse();
//HttpServletResponse httpResponse = (HttpServletResponse) event.getAsyncContext().getResponse();
if (httpResponse.getStatus() == HttpServletResponse.SC_OK || httpResponse.getStatus() == HttpServletResponse.SC_CREATED ) {
//some business logic
}
}
}, myRequestWrapper, httpServletResponse);
chain.doFilter(myRequestWrapper, response);
但添加上述“AsyncListener”实现会导致以下“IllegalStateException”：
https://164.99.175.139:8443/visual-analytics/proxy/elasticsearch/.kibana/search/test1?op_type=create java.lang.IllegalStateException: s=DISPATCHED i=true a=STARTED at org.eclipse.jetty.server.HttpChannelState.startAsync(HttpChannelState.java:264) at org.eclipse.jetty.server.Request.startAsync(Request.java:2235) at javax.servlet.ServletRequestWrapper.startAsync(ServletRequestWrapper.java:432) at javax.servlet.ServletRequestWrapper.startAsync(ServletRequestWrapper.java:432) at javax.servlet.ServletRequestWrapper.startAsync(ServletRequestWrapper.java:432) at org.eclipse.jetty.proxy.ProxyServlet.service(ProxyServlet.java:88) at javax.servlet.http.HttpServlet.service(HttpServlet.java:790) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:845) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1712) at com.netiq.sentinel.kibana.search.KibanaSearchFilter.doFilter(KibanaSearchFilter.java:249) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1699) at com.netiq.sentinel.kibana.proxy.AcceptEncodingHeaderModificationFilter.doFilter(AcceptEncodingHeaderModificationFilter.java:37) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1699) at com.netiq.sentinel.kibana.proxy.SecurityFilter.doFilter(SecurityFilter.java:41) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1699) at com.netiq.sentinel.kibana.proxy.AuditFilter.doFilter(AuditFilter.java:104) at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1699) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141) at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213) at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:119) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134) at org.eclipse.jetty.server.Server.handle(Server.java:534) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95) at org.eclipse.jetty.io.ssl.SslConnection.onFillable(SslConnection.java:202) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95) at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148) at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589) at java.lang.Thread.run(Thread.java:745)
上述堆栈跟踪中提到的“ProxyServlet.java”中的第 88 行代码如下：
final AsyncContext asyncContext = request.startAsync();
是否因为 startAsync() 方法在同一个请求上被调用两次而引发“IllegalStateException” - 第一次在我的过滤器中，第二次在 Jetty ProxyServlet 的 service() 方法中？如果是，是否无法在由 Jetty 的 ProxyServlet 终止的过滤器链中使用“AsyncListener”？
任何有关如何进一步进行的指示将不胜感激。期待任何回应...
【问题讨论】：
标签： java servlet-filters embedded-jetty servlet-3.0 jetty-9