我错过了什么？
AMQ版本5.13.2 Java 1.8.0_74 Windows 10
给定一个简单的测试用例，传输两个Object消息，一个包含数据，另一个是数据结束标记。只收到数据结束标记。
队列在作业开始时创建，并在作业完成后销毁。
如果我运行大量交易，我会看到大约50％的收货率。
日志清楚地表明接收器是在第一条消息放入队列之前启动的，两条消息都被放在队列中，但实际上只接收到第二条消息。
发送方和接收方都在同一个JVM上。每个都有自己的Session和Connection。
连接和队列设置代码：
@Override
public void beforeJob(JobExecution jobExecution) {
// TODO Auto-generated method stub
try {
jobParameters = jobExecution.getJobParameters();
readerConnection = connectionFactory.createConnection();
readerConnection.start();
writerConnection = connectionFactory.createConnection();
writerConnection.start();
jmsQueueManagementSession = writerConnection.createSession(false, Session.AUTO_ACKNOWLEDGE);
queueName = jobParameters.getString("jobName") + "." + jobExecution.getId();
queue = jmsQueueManagementSession.createQueue(getQueueName());
} catch (JMSException ex) {
throw new MaxisRuntimeException(
MaxisCodeHelperImpl.generateCode("MXAR", MXMODULE, JMS_RECEIVER_INITIALIZATION_ERROR), null);
}
}
发件人设置代码：
@Override
public void beforeStep(StepExecution stepExecution) {
this.stepExecution = stepExecution;
this.setJobExecution(stepExecution.getJobExecution());
try {
this.connection = jmsJobExecutionListener.getWriterConnection();
this.session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
this.messageProducer = session.createProducer(jmsJobExecutionListener.getQueue());
} catch (JMSException ex) {
throw new RuntimeException(ex.getMessage(), ex);
}
}
接收器设置代码：
@Override
@BeforeStep
public void beforeStep(StepExecution stepExecution) {
this.stepExecution = stepExecution;
this.setJobExecution(stepExecution.getJobExecution());
try {
this.connection = jmsJobExecutionListener.getReaderConnection();
this.jmsSession = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
this.messageConsumer = jmsSession.createConsumer(jmsJobExecutionListener.getQueue());
}
catch (JMSException ex)
{
throw new RuntimeException(ex.getMessage(), ex);
}
}
传输代码：
private void doSomeStuffInTransaction (final Object model) {
transactionTemplate.execute(new TransactionCallbackWithoutResult() {
@Override
protected void doInTransactionWithoutResult(TransactionStatus status) {
try {
doSomeStuff ( model );
ObjectMessage message = session.createObjectMessage(
(model.getRoot() == null)
? null
: model.getRoot().getContents().getId());
messageProducer.send(message);
logger.debug("Sent: {}", message.toString());
}catch (Exception e) {
//use this to rollback exception in case of exception
status.setRollbackOnly();
throw new RuntimeException(e.getmessage(), e);
}
}});
}
收件人代码：
public Object read() throws Exception,
UnexpectedInputException, ParseException,
NonTransientResourceException {
Object result = null;
logger.debug("Attempting to receive message on connection: ", connection.toString());
ObjectMessage msg = (ObjectMessage) messageConsumer.receive();
logger.debug("Received: {}", msg.toString());
result = msg.getObject();
return result;
}
记录剪辑：
DEBUG com.mylib.SelectedDataJmsReader - Attempting to receive message on connection:
... snip ...
*** First message ***
DEBUG org.apache.activemq.broker.region.Queue - localhost Message ID:zip-56502-1457640572818-4:2:2:1:1 sent to queue://Stuff via SQL.402
DEBUG org.apache.activemq.broker.region.Queue - queue://Stuff via SQL.402, subscriptions=2, memory=0%, size=1, pending=0 toPageIn: 1, Inflight: 0, pagedInMessages.size 0, pagedInPendingDispatch.size 0, enqueueCount: 1, dequeueCount: 0, memUsage:2214
DEBUG com.maxis.mxmove.core.SelectedDataJmsWriter - Sent: ActiveMQObjectMessage {commandId = 0, responseRequired = false, messageId = ID:zip-56502-1457640572818-4:2:2:1:1, originalDestination = null, originalTransactionId = null, producerId = null, destination = queue://Stuff via SQL.402, transactionId = null, expiration = 0, timestamp = 1457640610215, arrival = 0, brokerInTime = 0, brokerOutTime = 0, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = org.apache.activemq.util.ByteSequence@78cb27fd, marshalledProperties = null, dataStructure = null, redeliveryCounter = 0, size = 0, properties = null, readOnlyProperties = false, readOnlyBody = false, droppable = false, jmsXGroupFirstForConsumer = false}
INFO com.maxis.mxmove.core.SelectedDataJmsWriter - Committed 1 stuff to redo log and JMS queue
*** Second Message ***
INFO com.maxis.mxmove.core.SourceSelectionReaderImpl - Returning empty stuff and end-of-stream placeholder.
DEBUG org.apache.activemq.broker.region.Queue - localhost Message ID:zip-56502-1457640572818-4:2:2:1:2 sent to queue://Stuff via SQL.402
DEBUG org.apache.activemq.broker.region.Queue - queue://Stuff via SQL.402, subscriptions=2, memory=0%, size=2, pending=0 toPageIn: 1, Inflight: 1, pagedInMessages.size 1, pagedInPendingDispatch.size 0, enqueueCount: 2, dequeueCount: 0, memUsage:3155
DEBUG com.maxis.mxmove.core.SelectedDataJmsWriter - Sent: ActiveMQObjectMessage {commandId = 0, responseRequired = false, messageId = ID:zip-56502-1457640572818-4:2:2:1:2, originalDestination = null, originalTransactionId = null, producerId = null, destination = queue://Stuff via SQL.402, transactionId = null, expiration = 0, timestamp = 1457640610375, arrival = 0, brokerInTime = 0, brokerOutTime = 0, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = null, marshalledProperties = null, dataStructure = null, redeliveryCounter = 0, size = 0, properties = null, readOnlyProperties = false, readOnlyBody = false, droppable = false, jmsXGroupFirstForConsumer = false}
INFO com.maxis.mxmove.core.SelectedDataJmsWriter - Committed 1 stuff to redo log and JMS queue
*** We received the last message, not the first. We show two enqueues, and one dequeue.. ***
DEBUG com.maxis.mxmove.core.SelectedDataJmsReader - Received: ActiveMQObjectMessage {commandId = 7, responseRequired = true, messageId = ID:zip-56502-1457640572818-4:2:2:1:2, originalDestination = null, originalTransactionId = null, producerId = ID:zip-56502-1457640572818-4:2:2:1, destination = queue://Stuff via SQL.402, transactionId = null, expiration = 0, timestamp = 1457640610375, arrival = 0, brokerInTime = 1457640610375, brokerOutTime = 1457640610376, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = null, marshalledProperties = null, dataStructure = null, redeliveryCounter = 0, size = 1024, properties = null, readOnlyProperties = true, readOnlyBody = true, droppable = false, jmsXGroupFirstForConsumer = false}
INFO com.maxis.mxmove.core.SelectedDataJmsReader - executed read, found end-of-stream marker, returning null
DEBUG org.apache.activemq.broker.region.Queue - queue://Stuff via SQL.402, subscriptions=2, memory=0%, size=1, pending=0 toPageIn: 0, Inflight: 1, pagedInMessages.size 1, pagedInPendingDispatch.size 0, enqueueCount: 2, dequeueCount: 1, memUsage:1107
答案 0 :(得分：2)
在Receiver Setup代码中，请注意beforeStep（）方法是使用@BeforeStep注释的。我认为这意味着接收器正在设置两次，并且可能具有预取优化。这是验证的，因为日志显示了两个订阅。我不是一个沉重的JMS用户，我错误地认为一个是接收者而另一个是发送者。
@Override
@BeforeStep
public void beforeStep(StepExecution stepExecution) {
this.stepExecution = stepExecution;
this.setJobExecution(stepExecution.getJobExecution());
删除@BeforeStep注释后，日志只显示一个订阅
DEBUG org.apache.activemq.broker.region.Queue - queue://Workorders via SQL.408, subscriptions=1, memory=0%, size=1, pending=0 toPageIn: 0, Inflight: 1, pagedInMessages.size 1, pagedInPendingDispatch.size 0, enqueueCount: 1370, dequeueCount: 1369, memUsage:1024
下次当有人告诉我使用注射时代码是如何“干净”时，我可能会考虑应用Martial Arts Exchange