如何取消订阅持久主题订阅

Question

使用Stomp WebSockets连接到ActiveMQ服务器，我的extjs5浏览器web应用程序有许多主题订阅范围到面板。

下面是一个带有标题的主题订阅示例:

var sub = this.mqClient.subscribe('/topic/Status', this.onStatusMsg, 
{"ack":"auto","persistent":true,"activemq.retroactive":true,"selector":"TaskId = 1531","activemq.subscriptionName":"status-1531"} );

当用户完成主题订阅时，她关闭触发this.mqClient的面板。取消订阅(订阅)呼叫。

重新打开该面板将创建具有相同activemq的订阅。subscriptionName，它触发这个错误响应:

javax.jms.JMSException: Durable consumer is in use for client: 2015-05-28 15:29:32-0700.0.9276173142716289 and subscriptionName: status-1531
    at org.apache.activemq.broker.region.TopicRegion.addConsumer(TopicRegion.java:127)
    at org.apache.activemq.broker.region.RegionBroker.addConsumer(RegionBroker.java:427)
    at org.apache.activemq.broker.jmx.ManagedRegionBroker.addConsumer(ManagedRegionBroker.java:244)
    at org.apache.activemq.broker.BrokerFilter.addConsumer(BrokerFilter.java:102)
    at org.apache.activemq.advisory.AdvisoryBroker.addConsumer(AdvisoryBroker.java:104)
    at org.apache.activemq.broker.BrokerFilter.addConsumer(BrokerFilter.java:102)
    at org.apache.activemq.broker.BrokerFilter.addConsumer(BrokerFilter.java:102)
    at org.apache.activemq.broker.MutableBrokerFilter.addConsumer(MutableBrokerFilter.java:107)
    at org.apache.activemq.broker.TransportConnection.processAddConsumer(TransportConnection.java:667)
    at org.apache.activemq.command.ConsumerInfo.visit(ConsumerInfo.java:348)
    at org.apache.activemq.broker.TransportConnection.service(TransportConnection.java:335)
    at org.apache.activemq.broker.TransportConnection$1.onCommand(TransportConnection.java:189)
    at org.apache.activemq.transport.AbstractInactivityMonitor.onCommand(AbstractInactivityMonitor.java:270)
    at org.apache.activemq.transport.TransportSupport.doConsume(TransportSupport.java:83)
    at org.apache.activemq.transport.ws.jetty8.StompSocket.sendToActiveMQ(StompSocket.java:125)
    at org.apache.activemq.transport.stomp.ProtocolConverter.sendToActiveMQ(ProtocolConverter.java:199)
    at org.apache.activemq.transport.stomp.ProtocolConverter.onStompSubscribe(ProtocolConverter.java:663)
    at org.apache.activemq.transport.stomp.ProtocolConverter.onStompCommand(ProtocolConverter.java:257)
    at org.apache.activemq.transport.ws.jetty8.StompSocket.onMessage(StompSocket.java:82)
    at org.eclipse.jetty.websocket.WebSocketConnectionRFC6455$WSFrameHandler.onFrame(WebSocketConnectionRFC6455.java:850)
    at org.eclipse.jetty.websocket.WebSocketParserRFC6455.parseNext(WebSocketParserRFC6455.java:349)
    at org.eclipse.jetty.websocket.WebSocketConnectionRFC6455.handle(WebSocketConnectionRFC6455.java:225)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:696)
    at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:53)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
    at java.lang.Thread.run(Thread.java:745)

如何关闭持久主题订阅?

Answer 1

如果订阅当前处于活动状态(意味着订阅者当前处于连接和订阅状态)，则在STOMP中删除持久订阅需要两个步骤。

首先，客户端必须取消订阅，使订阅变为非活动状态:

String frame = "UNSUBSCRIBEn" + "destination:/topic/MyTopic" + "nn" + Stomp.NULL;

现在订阅处于非活动状态，可以通过使用最初用于创建它的订阅名称发出退订来永久删除它，如下所示:

String frame = "UNSUBSCRIBEn" + "destination:/topic/MyTopic" + "n" + "activemq.subscriptionName:MySubscriptionNamenn" + Stomp.NULL;

这将从ActiveMQ消息存储库中删除订阅及其持有的所有存储消息。