当我将Zuul连接到Eureka时，我收到以下错误：
[err] 42622092 [pool-2-thread-1] ERROR com.netflix.discovery.DiscoveryClient - Can't get a response from https://sd-eureka-01.th.net:8443/eureka/v2/apps/ZUUL/x.x.x.x
Can't contact any eureka nodes - possibly a security group issue?
[err] com.sun.jersey.api.client.ClientHandlerException: org.apache.http.NoHttpResponseException: sd-eureka-01.th.net:8443 failed to respond
[err] at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187)
[err] at com.sun.jersey.api.client.filter.GZIPContentEncodingFilter.handle(GZIPContentEncodingFilter.java:123)
[err] at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:28)
[err] at com.sun.jersey.api.client.Client.handle(Client.java:652)
[err] at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682)
[err] at com.sun.jersey.api.client.WebResource.put(WebResource.java:213)
[err] at com.netflix.discovery.DiscoveryClient.makeRemoteCall(DiscoveryClient.java:1108)
[err] at com.netflix.discovery.DiscoveryClient.makeRemoteCall(DiscoveryClient.java:1065)
[err] at com.netflix.discovery.DiscoveryClient.access$500(DiscoveryClient.java:110)
[err] at com.netflix.discovery.DiscoveryClient$HeartbeatThread.run(DiscoveryClient.java:1630)
[err] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[err] at java.util.concurrent.FutureTask.run(FutureTask.java:267)
[err] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1143)
[err] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:618)
[err] at java.lang.Thread.run(Thread.java:785)
[err] Caused by:
[err] org.apache.http.NoHttpResponseException: sd-eureka-01.th.net:8443 failed to respond
[err] at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:143)
[err] at [internal classes]
[err] at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:173)
[err] ... 14 more
[err] 42622098 [pool-2-thread-1] ERROR com.netflix.discovery.DiscoveryClient - DiscoveryClient_ZUUL/x.x.x.x - was unable to send heartbeat!
[err] com.sun.jersey.api.client.ClientHandlerException: org.apache.http.NoHttpResponseException: sd-eureka-01.th.net:8443 failed to respond
[err] at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187)
[err] at com.sun.jersey.api.client.filter.GZIPContentEncodingFilter.handle(GZIPContentEncodingFilter.java:123)
[err] at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:28)
[err] at com.sun.jersey.api.client.Client.handle(Client.java:652)
[err] at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682)
[err] at com.sun.jersey.api.client.WebResource.put(WebResource.java:213)
[err] at com.netflix.discovery.DiscoveryClient.makeRemoteCall(DiscoveryClient.java:1108)
[err] at com.netflix.discovery.DiscoveryClient.makeRemoteCall(DiscoveryClient.java:1065)
[err] at com.netflix.discovery.DiscoveryClient.access$500(DiscoveryClient.java:110)
[err] at com.netflix.discovery.DiscoveryClient$HeartbeatThread.run(DiscoveryClient.java:1630)
[err] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[err] at java.util.concurrent.FutureTask.run(FutureTask.java:267)
[err] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1143)
[err] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:618)
[err] at java.lang.Thread.run(Thread.java:785)
[err] Caused by:
[err] org.apache.http.NoHttpResponseException: sd-eureka-01.th.net:8443 failed to respond
[err] at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:143)
[err] at [internal classes]
[err] at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:173)
[err] ... 14 more
然而，当我检查我的尤里卡Sever时，我看到Zuul经常向Eureka发送心跳，其状态显示为up。我在Tomcat上运行Zuul和Eureka。这个问题可能是由于HttpClient在一段空闲时间后关闭了连接，但是Zuul并不知道它。一旦收到错误，它就会创建一个新连接并再次发送请求。
Zuul每隔30秒向Eureka发送一次心跳。是否可以在Tomcat上更改一些不关闭连接的设置？