spring的RabbitTemplate 接收Message源码导读

1，首先调用类SimpleMessageListenerContainer的内部类AsyncMessageProcessingConsumer的run方法。内部类的主要属性如下

private final BlockingQueueConsumer consumer;private final CountDownLatch start;private volatile FatalListenerStartupException startupException;

2，内部类的run方法如下

boolean aborted = false;int consecutiveIdles = 0;int consecutiveMessages = 0;try {try {SimpleMessageListenerContainer.this.redeclareElementsIfNecessary();this.consumer.start();this.start.countDown();}catch (QueuesNotAvailableException e) {if (SimpleMessageListenerContainer.this.missingQueuesFatal) {throw e;}else {this.start.countDown();handleStartupFailure(e);throw e;}}catch (FatalListenerStartupException ex) {throw ex;}catch (Throwable t) {this.start.countDown();handleStartupFailure(t);throw t;}if (SimpleMessageListenerContainer.this.transactionManager != null) {/* * Register the consumer's channel so it will be used by the transaction manager * if it's an instance of RabbitTransactionManager. */ConsumerChannelRegistry.registerConsumerChannel(consumer.getChannel(), getConnectionFactory());}// Always better to stop receiving as soon as possible if// transactionalboolean continuable = false;while (isActive(this.consumer) || continuable) {try {// Will come back false when the queue is drainedcontinuable = receiveAndExecute(this.consumer) && !isChannelTransacted();if (SimpleMessageListenerContainer.this.maxConcurrentConsumers != null) {if (continuable) {consecutiveIdles = 0;if (consecutiveMessages++ > SimpleMessageListenerContainer.this.consecutiveActiveTrigger) {considerAddingAConsumer();consecutiveMessages = 0;}}else {consecutiveMessages = 0;if (consecutiveIdles++ > SimpleMessageListenerContainer.this.consecutiveIdleTrigger) {considerStoppingAConsumer(this.consumer);consecutiveIdles = 0;}}}}catch (ListenerExecutionFailedException ex) {// Continue to process, otherwise re-throw}catch (AmqpRejectAndDontRequeueException rejectEx) {/* *  These will normally be wrapped by an LEFE if thrown by the *  listener, but we will also honor it if thrown by an *  error handler. */}}}catch (InterruptedException e) {logger.debug("Consumer thread interrupted, processing stopped.");Thread.currentThread().interrupt();aborted = true;}catch (QueuesNotAvailableException ex) {if (SimpleMessageListenerContainer.this.missingQueuesFatal) {logger.error("Consumer received fatal exception on startup", ex);this.startupException = ex;// Fatal, but no point re-throwing, so just abort.aborted = true;}}catch (FatalListenerStartupException ex) {logger.error("Consumer received fatal exception on startup", ex);this.startupException = ex;// Fatal, but no point re-throwing, so just abort.aborted = true;}catch (FatalListenerExecutionException ex) {logger.error("Consumer received fatal exception during processing", ex);// Fatal, but no point re-throwing, so just abort.aborted = true;}catch (ShutdownSignalException e) {if (RabbitUtils.isNormalShutdown(e)) {if (logger.isDebugEnabled()) {logger.debug("Consumer received Shutdown Signal, processing stopped: " + e.getMessage());}}else {this.logConsumerException(e);}}catch (AmqpIOException e) {if (e.getCause() instanceof IOException && e.getCause().getCause() instanceof ShutdownSignalException&& e.getCause().getCause().getMessage().contains("in exclusive use")) {logger.warn(e.getCause().getCause().toString());}else {this.logConsumerException(e);}}catch (Error e) {logger.error("Consumer thread error, thread abort.", e);aborted = true;}catch (Throwable t) {this.logConsumerException(t);}finally {if (SimpleMessageListenerContainer.this.transactionManager != null) {ConsumerChannelRegistry.unRegisterConsumerChannel();}}// In all cases count down to allow container to progress beyond startupstart.countDown();if (!isActive(consumer) || aborted) {logger.debug("Cancelling " + this.consumer);try {this.consumer.stop();synchronized (consumersMonitor) {if (SimpleMessageListenerContainer.this.consumers != null) {SimpleMessageListenerContainer.this.consumers.remove(this.consumer);}}}catch (AmqpException e) {logger.info("Could not cancel message consumer", e);}if (aborted) {logger.error("Stopping container from aborted consumer");stop();}}else {logger.info("Restarting " + this.consumer);restart(this.consumer);}

3，run方法调用类BlockingQueueConsumer的start方法，BlockingQueueConsumer的属性如下

private final BlockingQueue<Delivery> queue;// When this is non-null the connection has been closed (should never happen in normal operation).private volatile ShutdownSignalException shutdown;private final String[] queues;private final int prefetchCount;private final boolean transactional;private Channel channel;private RabbitResourceHolder resourceHolder;private InternalConsumer consumer;private final AtomicBoolean cancelled = new AtomicBoolean(false);private volatile long shutdownTimeout;private final AtomicBoolean cancelReceived = new AtomicBoolean(false);private final AcknowledgeMode acknowledgeMode;private final ConnectionFactory connectionFactory;private final MessagePropertiesConverter messagePropertiesConverter;private final ActiveObjectCounter<BlockingQueueConsumer> activeObjectCounter;private final Map<String, Object> consumerArgs = new HashMap<String, Object>();private final boolean exclusive;private final Set<Long> deliveryTags = new LinkedHashSet<Long>();private final boolean defaultRequeuRejected;private final CountDownLatch suspendClientThread = new CountDownLatch(1);private final Collection<String> consumerTags = Collections.synchronizedSet(new HashSet<String>());private final Set<String> missingQueues = Collections.synchronizedSet(new HashSet<String>());private final long retryDeclarationInterval = 60000;private long lastRetryDeclaration;

4，调用ConnectionFactoryUtils获取connection

private static RabbitResourceHolder doGetTransactionalResourceHolder(ConnectionFactory connectionFactory,ResourceFactory resourceFactory) {Assert.notNull(connectionFactory, "ConnectionFactory must not be null");Assert.notNull(resourceFactory, "ResourceFactory must not be null");RabbitResourceHolder resourceHolder = (RabbitResourceHolder) TransactionSynchronizationManager.getResource(connectionFactory);if (resourceHolder != null) {Channel channel = resourceFactory.getChannel(resourceHolder);if (channel != null) {return resourceHolder;}}RabbitResourceHolder resourceHolderToUse = resourceHolder;if (resourceHolderToUse == null) {resourceHolderToUse = new RabbitResourceHolder();}Connection connection = resourceFactory.getConnection(resourceHolderToUse);Channel channel = null;try {/* * If we are in a listener container, first see if there's a channel registered * for this consumer and the consumer is using the same connection factory. */channel = ConsumerChannelRegistry.getConsumerChannel(connectionFactory);if (channel == null && connection == null) {connection = resourceFactory.createConnection();resourceHolderToUse.addConnection(connection);}if (channel == null) {channel = resourceFactory.createChannel(connection);}resourceHolderToUse.addChannel(channel, connection);if (resourceHolderToUse != resourceHolder) {bindResourceToTransaction(resourceHolderToUse, connectionFactory,resourceFactory.isSynchedLocalTransactionAllowed());}return resourceHolderToUse;} catch (IOException ex) {RabbitUtils.closeChannel(channel);RabbitUtils.closeConnection(connection);throw new AmqpIOException(ex);}}

 

5，调用类CachingConnectionFactory的createConnection

@Overridepublic final Connection createConnection() throws AmqpException {synchronized (this.connectionMonitor) {if (this.cacheMode == CacheMode.CHANNEL) {if (this.connection == null) {this.connection = new ChannelCachingConnectionProxy(super.createBareConnection());// invoke the listener *after* this.connection is assignedgetConnectionListener().onCreate(connection);}return this.connection;}else if (this.cacheMode == CacheMode.CONNECTION) {ChannelCachingConnectionProxy connection = null;while (connection == null && !this.idleConnections.isEmpty()) {connection = this.idleConnections.poll();if (connection != null) {if (!connection.isOpen()) {if (logger.isDebugEnabled()) {logger.debug("Removing closed connection '" + connection + "'");}connection.notifyCloseIfNecessary();this.openConnections.remove(connection);this.openConnectionNonTransactionalChannels.remove(connection);this.openConnectionTransactionalChannels.remove(connection);connection = null;}}}if (connection == null) {connection = new ChannelCachingConnectionProxy(super.createBareConnection());getConnectionListener().onCreate(connection);if (logger.isDebugEnabled()) {logger.debug("Adding new connection '" + connection + "'");}this.openConnections.add(connection);this.openConnectionNonTransactionalChannels.put(connection, new LinkedList<ChannelProxy>());this.openConnectionTransactionalChannels.put(connection, new LinkedList<ChannelProxy>());}else {if (logger.isDebugEnabled()) {logger.debug("Obtained connection '" + connection + "' from cache");}}return connection;}}return null;}

6，调用类ConnectionFactory的newConnection方法

    public Connection newConnection(ExecutorService executor, Address[] addrs)        throws IOException    {        FrameHandlerFactory fhFactory = createFrameHandlerFactory();        ConnectionParams params = params(executor);        if (isAutomaticRecoveryEnabled()) {            // see com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory#newConnection            AutorecoveringConnection conn = new AutorecoveringConnection(params, fhFactory, addrs);            conn.init();            return conn;        } else {            IOException lastException = null;            for (Address addr : addrs) {                try {                    FrameHandler handler = fhFactory.create(addr);                    AMQConnection conn = new AMQConnection(params, handler);                    conn.start();                    return conn;                } catch (IOException e) {                    lastException = e;                }            }            throw (lastException != null) ? lastException : new IOException("failed to connect");        }    }

7，调用AMQConnection的start方法

 public void start()        throws IOException    {        initializeConsumerWorkService();        initializeHeartbeatSender();        this._running = true;        // Make sure that the first thing we do is to send the header,        // which should cause any socket errors to show up for us, rather        // than risking them pop out in the MainLoop        AMQChannel.SimpleBlockingRpcContinuation connStartBlocker =            new AMQChannel.SimpleBlockingRpcContinuation();        // We enqueue an RPC continuation here without sending an RPC        // request, since the protocol specifies that after sending        // the version negotiation header, the client (connection        // initiator) is to wait for a connection.start method to        // arrive.        _channel0.enqueueRpc(connStartBlocker);        try {            // The following two lines are akin to AMQChannel's            // transmit() method for this pseudo-RPC.            _frameHandler.setTimeout(HANDSHAKE_TIMEOUT);            _frameHandler.sendHeader();        } catch (IOException ioe) {            _frameHandler.close();            throw ioe;        }        // start the main loop going        MainLoop loop = new MainLoop();        final String name = "AMQP Connection " + getHostAddress() + ":" + getPort();        mainLoopThread = Environment.newThread(threadFactory, loop, name);        mainLoopThread.start();        // after this point clear-up of MainLoop is triggered by closing the frameHandler.        AMQP.Connection.Start connStart = null;        AMQP.Connection.Tune connTune = null;        try {            connStart =                (AMQP.Connection.Start) connStartBlocker.getReply().getMethod();            _serverProperties = Collections.unmodifiableMap(connStart.getServerProperties());            Version serverVersion =                new Version(connStart.getVersionMajor(),                            connStart.getVersionMinor());            if (!Version.checkVersion(clientVersion, serverVersion)) {                throw new ProtocolVersionMismatchException(clientVersion,                                                           serverVersion);            }            String[] mechanisms = connStart.getMechanisms().toString().split(" ");            SaslMechanism sm = this.saslConfig.getSaslMechanism(mechanisms);            if (sm == null) {                throw new IOException("No compatible authentication mechanism found - " +                        "server offered [" + connStart.getMechanisms() + "]");            }            LongString challenge = null;            LongString response = sm.handleChallenge(null, this.username, this.password);            do {                Method method = (challenge == null)                    ? new AMQP.Connection.StartOk.Builder()                                    .clientProperties(_clientProperties)                                    .mechanism(sm.getName())                                    .response(response)                          .build()                    : new AMQP.Connection.SecureOk.Builder().response(response).build();                try {                    Method serverResponse = _channel0.rpc(method).getMethod();                    if (serverResponse instanceof AMQP.Connection.Tune) {                        connTune = (AMQP.Connection.Tune) serverResponse;                    } else {                        challenge = ((AMQP.Connection.Secure) serverResponse).getChallenge();                        response = sm.handleChallenge(challenge, this.username, this.password);                    }                } catch (ShutdownSignalException e) {                    Method shutdownMethod = e.getReason();                    if (shutdownMethod instanceof AMQP.Connection.Close) {                        AMQP.Connection.Close shutdownClose =  (AMQP.Connection.Close) shutdownMethod;                        if (shutdownClose.getReplyCode() == AMQP.ACCESS_REFUSED) {                            throw new AuthenticationFailureException(shutdownClose.getReplyText());                        }                    }                    throw new PossibleAuthenticationFailureException(e);                }            } while (connTune == null);        } catch (ShutdownSignalException sse) {            _frameHandler.close();            throw AMQChannel.wrap(sse);        } catch(IOException ioe) {            _frameHandler.close();            throw ioe;        }        try {            int channelMax =                negotiateChannelMax(this.requestedChannelMax,                                    connTune.getChannelMax());            _channelManager = instantiateChannelManager(channelMax, threadFactory);            int frameMax =                negotiatedMaxValue(this.requestedFrameMax,                                   connTune.getFrameMax());            this._frameMax = frameMax;            int heartbeat =                negotiatedMaxValue(this.requestedHeartbeat,                                   connTune.getHeartbeat());            setHeartbeat(heartbeat);            _channel0.transmit(new AMQP.Connection.TuneOk.Builder()                                .channelMax(channelMax)                                .frameMax(frameMax)                                .heartbeat(heartbeat)                              .build());            _channel0.exnWrappingRpc(new AMQP.Connection.Open.Builder()                                      .virtualHost(_virtualHost)                                    .build());        } catch (IOException ioe) {            _heartbeatSender.shutdown();            _frameHandler.close();            throw ioe;        } catch (ShutdownSignalException sse) {            _heartbeatSender.shutdown();            _frameHandler.close();            throw AMQChannel.wrap(sse);        }        // We can now respond to errors having finished tailoring the connection        this._inConnectionNegotiation = false;        return;    }

8，默认queue以及Channel的值

Queue [name=app_queue, durable=true, autoDelete=false, exclusive=false, arguments=null]

Cached Rabbit Channel: AMQChannel(amqp://ad@192.168.120.12:5672/,1)

9，调用RabbitAdmin完成相关通道和绑定等的创建

10，ConnectionFactoryUtils.getTransactionalResourceHolder完成后，开始建立消费者BlockingQueueConsumer的start方法中

this.consumer = new InternalConsumer(channel);this.deliveryTags.clear();this.activeObjectCounter.add(this);

11，SimpleMessageListenerContainer的内部类AsyncMessageProcessingConsumer的run方法中调用

while (isActive(this.consumer) || continuable) {try {// Will come back false when the queue is drainedcontinuable = receiveAndExecute(this.consumer) && !isChannelTransacted();if (SimpleMessageListenerContainer.this.maxConcurrentConsumers != null) {if (continuable) {consecutiveIdles = 0;if (consecutiveMessages++ > SimpleMessageListenerContainer.this.consecutiveActiveTrigger) {considerAddingAConsumer();consecutiveMessages = 0;}}else {consecutiveMessages = 0;if (consecutiveIdles++ > SimpleMessageListenerContainer.this.consecutiveIdleTrigger) {considerStoppingAConsumer(this.consumer);consecutiveIdles = 0;}}}}catch (ListenerExecutionFailedException ex) {// Continue to process, otherwise re-throw}catch (AmqpRejectAndDontRequeueException rejectEx) {/* *  These will normally be wrapped by an LEFE if thrown by the *  listener, but we will also honor it if thrown by an *  error handler. */}}

 

12，后续调用业务onmessage见下图

 

 

注意：消费者默认属性

 

acknowledgeMode  prefetchCount=1
AcknowledgeMode AutoAck