[英]Oracle AQ Prioritised JMS messages delivered in reverse priority order
我這樣創建了一個oracle隊列
execute dbms_aqadm.create_queue_table (
queue_table => 'priorityqueue',
sort_list => 'PRIORITY,ENQ_TIME',
queue_payload_type => 'sys.aq$_jms_map_message',
compatible => '8.1.0');
execute dbms_aqadm.create_queue (
queue_name => 'priorityqueue',
queue_table => 'priorityqueue');
execute dbms_aqadm.start_queue (
queue_name => 'priorityqueue');
然后,我使用spring JMSTemplate
發送消息,如下所示:
ConnectionFactory connectionFactory = AQjmsFactory.getQueueConnectionFactory(dataSource);
JmsTemplate jmsTemplate = new JmsTemplate(connectionFactory);
jmsTemplate.setExplicitQosEnabled(true);
MessageCreator messageCreator = new MessageCreator() {
@Override
public Message createMessage(Session session) throws JMSException {
MapMessage message = session.createMapMessage();
// ... set some properties
message.setJMSPriority(priority);
return message;
}
};
jmsTemplate.setPriority(priority);
jmsTemplate.send("priorityqueue", messageCreator);
如果我從priorityqueue
select
所有內容,則可以看到消息以不同的優先級放在那里:
select q_name, msgid, priority, state from priorityqueue;
Q_NAME MSGID PRIORITY STATE
PRIORITYQUEUE 1297D3F58D41208FE05400215A97112C 1 0
PRIORITYQUEUE 1297D3F58D43208FE05400215A97112C 9 0
PRIORITYQUEUE 1297D3F58D45208FE05400215A97112C 4 0
接下來,我使用消息...沒什么特別的-像這樣:
ConnectionFactory connectionFactory = AQjmsFactory.getQueueConnectionFactory(oracleDataSource);
Connection connection = connectionFactory.createConnection();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
Queue loggerQueue = session.createQueue("priorityqueue");
MessageConsumer consumer = session.createConsumer(loggerQueue);
int count = 0;
while (true) {
connection.start();
Message message = consumer.receive(1000);
if (message == null) {
break;
}
count++;
System.out.println(count + ".\tPriority [" + message.getJMSPriority() + "]");
}
connection.close();
但是輸出看起來像這樣:
- 優先級[1]
- 優先級[4]
- 優先級[9]
何時應為9、4、1。
java.jms.Message的文檔明確指出, [t]he JMS API defines ten levels of priority value, with 0 as the lowest priority and 9 as the highest.
我究竟做錯了什么? 我研究過創建按優先級從高到低排序的隊列,但CREATE_QUEUE_TABLE
文檔指出, sort_list
是[t]he columns to be used as the sort key in ascending order
即看起來好像不是降序是一個選項。
另外-發送時,我設置了兩次優先級-一次在消息上,一次在jmsTemplate
。 我真的應該這樣做嗎?
Spring的JmsTemplate
不支持按消息優先級。 您需要按照本文中的描述子類化JmsTemplate
: https : //aminsblog.wordpress.com/2010/04/27/publishing-qos-priority-enabled-messages-using-spring-jms-template-2/
public class QoSEnabledJmsTemplate extends JmsTemplate {
protected void doSend(MessageProducer producer, Message message) throws JMSException {
producer.send(message, getDeliveryMode(), message.getJMSPriority(), getTimeToLive());
}
}
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