我遇到了RabbitMQ Work Queue实现的问题。我当前在Tomcat中运行它，并且我有以下类不断地对队列中的新任务进行监视。但是在一两天之后，突然它表现得很奇怪，其中对象 DeliveryOK 通过channel.queueDeclare返回（taskQueueName，isDurable，false，false，null）; 总是零。 （我在下面的日志中打印出这个＆＃34;当前的poolSize＆＃34;）。
但是在Rabbit admin（ ./ rabbitmqadmin list queues或RabbitMq Admin portal ）中，它总是返回一个大于零的数字（比如队列中的1267条消息）。并且它不会减少到零直到我重新启动tomcat，下面的类只能检测到队列中实际上有一些消息。
最初我认为这个类以某种方式被终止，但它能够消耗那些新到达的消息。它不会消耗那些留在队列中的1267条消息。例如，队列中的消息1267在重新启动tomcat之前不会消耗。
从下面的代码中，是因为有缺陷的实现还是有更好的方法来专门为RabbitMQ实现队列使用者？我已经阅读了相关的帖子帖子（Producer/Consumer threads using a Queue），但我不确定它是否有帮助。
此外，下面的此消费者实现是否无法在RunTimeException中存活？
MqConsumer Class：
@Service
public class MqConsumer implements Runnable{
private static final Logger logger = LoggerFactory.getLogger(MqConsumer.class);
private final int MAX_ALERT_THRESHOLD = 10000;
@Autowired
private AsynchSystemConnections asynchSystemConnections;
public MqConsumer(){
}
@PostConstruct
private void init() {
(new Thread(new MqConsumer(asynchSystemConnections))).start();
}
public MqConsumer(AsynchSystemConnections asynchSystemConnections){
this.asynchSystemConnections = asynchSystemConnections;
}
@Override
public void run() {
logger.info("Execute Consumer instance...");
while (true) { // infinite loop until it die due server restart
boolean toSleep = consume(asynchSystemConnections);
if (toSleep){
logger.error("Sleeping for 1 second...");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
logger.error("", e);
}
}
}
}
private boolean consume(AsynchSystemConnections asynchSystemConnections) {
com.rabbitmq.client.Connection mqConnection = null;
Channel mqChannel = null;
DatasiftMq dMq = null;
try {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost(asynchSystemConnections.getMqServerHost());
mqConnection = factory.newConnection();
mqChannel = mqConnection.createChannel();
//consumePushInteractionJob method will forward to AsynchTwService.consume(connection, channel, AsynchTwService.PUSH_INTERACTION_QUEUE )
dMq = asynchSystemConnections.getAsynchService().consumePushInteractionJob(mqConnection, mqChannel);
int poolSize = asynchSystemConnections.getAsynchService().getPushInteractionQueueSize();
logger.info("Current poolSize: " + poolSize);
} catch(NullPointerException e) {
logger.error("", e);
if (dMq != null) {
try {
logger.error("Removing JSON with" + dMq.getLogHeader(dMq));
asynchSystemConnections.getAsynchService().ack(mqChannel, dMq.getDelivery());
logger.error("Removed JSON with" + dMq.getLogHeader(dMq));
} catch (IOException e1) {
logger.error("Remove JSON Failed: ", e);
}
}
return true;
} catch (IOException e) {
logger.error("Unable to create new MQ Connection from factory.", e);
return true;
} catch (InterruptedException e) {
logger.error("", e);
return true;
} catch (ClassNotFoundException e) {
logger.error("", e);
return true;
} catch (Exception e) {
logger.error("Big problem, better solve this fast!!", e);
asynchSystemConnections.getNotificationService().notifySystemException(null, e);
return true;
} finally {
try {
asynchSystemConnections.getAsynchService().ack(mqChannel, dMq.getDelivery());
asynchSystemConnections.getAsynchService().disconnect(mqConnection, mqChannel);
} catch (IOException e) {
logger.error("", e);
}
}
return false;
}
AsynchTwService类：
@Service("asynchTwService")
public class AsynchTwService implements AsynchService {
static final String FAVOURITE_COUNT_QUEUE = "favourite_count_queue";
static final String FRIENDS_FOLLOWERS_QUEUE = "friends_followers_queue";
static final String DIRECT_MESSAGE_RECEIVE_QUEUE = "direct_message_receive_queue";
static final String PUSH_INTERACTION_QUEUE = "push_interaction_queue";
private static String mqServerHost;
private static final Logger logger = LoggerFactory.getLogger(AsynchTwService.class);
private static final boolean isDurable = true;
private boolean autoAck = false;
private ConcurrentHashMap<String, Integer> currentQueueSize = new ConcurrentHashMap<String, Integer>();
@Override
public Connection getConnection() throws IOException{
ConnectionFactory factory = new ConnectionFactory();
factory.setHost(mqServerHost);
return factory.newConnection();
}
@Override
public void produce(Connection connection, Channel channel, Object object, String taskQueueName) throws IOException {
sendToQueue(connection, channel, object, taskQueueName);
}
@Override
public QueueItem consume(Connection connection, Channel channel, String taskQueueName) throws IOException, InterruptedException, ClassNotFoundException{
Serializer serializer = new Serializer();
try {
Delivery delivery = listenFromQueue(connection, channel, taskQueueName);
Object messageObj = serializer.toObject(delivery.getBody());
QueueItem queueItem = (QueueItem)messageObj;
queueItem.setDelivery(delivery);
return queueItem;
} catch (InterruptedException e) {
throw e;
} catch (ClassNotFoundException e) {
logger.error("Unable to serialize the message to QueueItem object", e);
throw e;
}
}
@Override
public int getQueueSize(String taskQueueName){
return this.currentQueueSize.get(taskQueueName);
}
private Delivery listenFromQueue(Connection connection, Channel channel, String taskQueueName) throws IOException, InterruptedException, ClassNotFoundException{
try {
DeclareOk ok = channel.queueDeclare(taskQueueName, isDurable, false, false, null);
currentQueueSize.put(taskQueueName, ok.getMessageCount());
logger.info("Queue ("+ taskQueueName + ") has items: " +ok.getMessageCount());
} catch (IOException e) {
// TODO Auto-generated catch block
}
logger.info(" [*] Consuming "+taskQueueName+" message...");
QueueingConsumer consumer = new QueueingConsumer(channel);
try {
channel.basicConsume(taskQueueName, autoAck, consumer);
} catch (IOException e) {
logger.error("", e);
}
try {
QueueingConsumer.Delivery delivery = consumer.nextDelivery();
return delivery;
} catch (ShutdownSignalException e) {
logger.error("Unable to retrieve message from Queue", e);
throw e;
} catch (ConsumerCancelledException e) {
logger.error("Unable to retrieve message from Queue", e);
throw e;
} catch (InterruptedException e) {
logger.error("Unable to retrieve message from Queue", e);
throw e;
}
}
private void sendToQueue(Connection connection, Channel channel, Object object, String taskQueueName) throws IOException{
//Initialization, create Message Queue broker connection
try{
channel.queueDeclare(taskQueueName, isDurable, false, false, null);
}catch(IOException e) {
logger.error(e.getMessage());
logger.error("Error create Message Queue connection for queue name:" + taskQueueName, e);
throw e;
}
//send message to broker
try {
long start = System.currentTimeMillis();
Serializer serializer = new Serializer();
logger.info("Sending Twitter QueueItem to Message Queue...");
channel.basicPublish("", taskQueueName, MessageProperties.PERSISTENT_TEXT_PLAIN,
serializer.toBytes(object));
logger.info("Queue successfully sent, process took: " + (System.currentTimeMillis()-start)+ "ms");
} catch (IOException e) {
logger.error("Error while sending object to queue : " + taskQueueName, e);
throw e;
}
}
public static String getMqServerHost() {
return mqServerHost;
}
public static void setMqServerHost(String mqServerHost) {
AsynchTwService.mqServerHost = mqServerHost;
}
@Override
public void disconnect(Connection connection, Channel channel) throws IOException{
try {
if (channel != null){
if (channel.isOpen()){
channel.close();
}
}
if (connection != null){
if (connection.isOpen()){
connection.close();
}
}
logger.debug("MQ Channel Disconnected");
} catch (IOException e) {
throw e;
}
}
@Override
public void ack(Channel channel, QueueingConsumer.Delivery delivery) throws IOException {
// this is made as another method call is to avoid Ack too fast un intentionally
try {
channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
logger.info("[x] acked" );
} catch (IOException e) {
logger.error("Unable Acknowledge Queue Message", e);
throw e;
}
}
@Override
public DatasiftMq consumeDatasiftInteraction(Connection connection, Channel channel,
String taskQueueName) throws IOException, InterruptedException, ClassNotFoundException {
Serializer serializer = new Serializer();
try {
Delivery delivery = listenFromQueue(connection, channel, taskQueueName);
Object messageObj = serializer.toObject(delivery.getBody());
DatasiftMq dto = (DatasiftMq)messageObj;
dto.setDelivery(delivery);
return dto;
} catch (InterruptedException e) {
throw e;
} catch (ClassNotFoundException e) {
logger.error("Unable to serialize the message to DatasiftDTO object", e);
throw e;
}
}
@Override
public void reQueue(Channel channel, Delivery delivery) throws IOException {
try {
channel.basicNack(delivery.getEnvelope().getDeliveryTag(), false, true);
logger.info("[x] Nacked" );
} catch (IOException e) {
logger.error("Unable Acknowledge Queue Message", e);
throw e;
}
}
}
答案 0 :(得分：2)
好像你在这里缺少一些基础知识。
取自here以及我的一些代码。 在消费者线程之外设置连接：
//executed once
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("someHost");
factory.setUsername("user");
factory.setPassword("pass");
Connection connection = factory.newConnection();
你在线程中要做的事情：
//Consumer - executed in a Thread
QueueingConsumer consumer = new QueueingConsumer(connection.createChannel());
boolean autoAck = false;
channel.basicConsume("hello", autoAck, consumer);
while (!Thread.current().isInterrupted())) {
QueueingConsumer.Delivery delivery = consumer.nextDelivery();
//...
channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
}
总的来说，我仍然建议您查看它完美集成的spring-amqp库。