死信队列监听补充

死信队列监听一开始的逻辑是正确的，但关于监听的内容以及动态判断有了新的思路，不断发现不断改善。

监听新思路

1.不必去破坏生产者消费者的关系，去创建死信队列的对应消费者，如果不同队列去创建对应的死信队列监听，没什么意义，复用刚开始的思路进行更改。mq配置更改指定监听死信队列，死信队列的名称是可以配置指定的

@Bean
    public ActiveMQConnectionFactory connectionFactory() throws JMSException {
        ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory(brokerurl);
        factory.setTrustAllPackages(true);//信任所有包下的序列化对象，解决无法发送对象消息
        javax.jms.Connection connection = factory.createConnection();
        connection.start();
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Queue queue = session.createQueue("ActiveMQ.DLQ");
        MessageConsumer messageConsumer = session.createConsumer(queue);
        messageConsumer.setMessageListener(new QueueListener());
        factory.setUserName(userName);
        factory.setPassword(password);
        return factory;
    }

新建监听类

/**
 * @author zhaokkstart
 * @create 2020-09-11 11:18
 */
public class QueueListener implements MessageListener {
    @Override
    public void onMessage(Message message) {
        System.out.println("****消费者的消息："+message);
    }
}

看下能从message获取到什么东西

public interface Message {
    static final int DEFAULT_DELIVERY_MODE = DeliveryMode.PERSISTENT;
    static final int DEFAULT_PRIORITY = 4;
    static final long DEFAULT_TIME_TO_LIVE = 0;
    String getJMSMessageID() throws JMSException;
    void setJMSMessageID(String id) throws JMSException;
    long getJMSTimestamp() throws JMSException;
    void setJMSTimestamp(long timestamp) throws JMSException;
    byte[] getJMSCorrelationIDAsBytes() throws JMSException;
    void setJMSCorrelationIDAsBytes(byte[] correlationID) throws JMSException;
    void setJMSCorrelationID(String correlationID) throws JMSException;
    String getJMSCorrelationID() throws JMSException;
    Destination getJMSReplyTo() throws JMSException;
    void setJMSReplyTo(Destination replyTo) throws JMSException;
    Destination getJMSDestination() throws JMSException;
    void setJMSDestination(Destination destination) throws JMSException;
    int getJMSDeliveryMode() throws JMSException;
    void setJMSDeliveryMode(int deliveryMode) throws JMSException;
    boolean getJMSRedelivered() throws JMSException;
    void setJMSRedelivered(boolean redelivered) throws JMSException;
    String getJMSType() throws JMSException;
    void setJMSType(String type) throws JMSException;
    long getJMSExpiration() throws JMSException;
    void setJMSExpiration(long expiration) throws JMSException;
    int getJMSPriority() throws JMSException;
    void setJMSPriority(int priority) throws JMSException;
    void clearProperties() throws JMSException;
    boolean propertyExists(String name) throws JMSException;
    boolean getBooleanProperty(String name) throws JMSException;
    byte getByteProperty(String name) throws JMSException;
    short getShortProperty(String name) throws JMSException;
    int getIntProperty(String name) throws JMSException;
    long getLongProperty(String name) throws JMSException;
    float getFloatProperty(String name) throws JMSException;
    double getDoubleProperty(String name) throws JMSException;
    String getStringProperty(String name) throws JMSException;
    Object getObjectProperty(String name) throws JMSException;
    Enumeration getPropertyNames() throws JMSException;
    void setBooleanProperty(String name, boolean value) throws JMSException;
    void setByteProperty(String name, byte value) throws JMSException;
    void setShortProperty(String name, short value) throws JMSException;
    void setIntProperty(String name, int value) throws JMSException;
    void setLongProperty(String name, long value) throws JMSException;
    void setFloatProperty(String name, float value) throws JMSException;
    void setDoubleProperty(String name, double value) throws JMSException;
    void setStringProperty(String name, String value) throws JMSException;
    void setObjectProperty(String name, Object value) throws JMSException;
    void acknowledge() throws JMSException;
    void clearBody() throws JMSException;}

还是对象里的那点东西，到有个新思路

commandId = 5,
    responseRequired = true,
    messageId = ID: kk - 59648 - 1599635155556 - 1: 239: 1: 1: 1, 
    originalDestination = null, originalTransactionId = null, 
    producerId = ID: kk - 59648 - 1599635155556 - 1: 239: 1: 1, 
    destination = queue: //add_xxxxxx, 
    transactionId = null, expiration = 0, timestamp = 1599636301936, arrival = 0, 
    brokerInTime = 1599636301937, brokerOutTime = 1599636302110, 
    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@54eae153, 
    marshalledProperties = org.apache.activemq.util.ByteSequence@1318dd4d,
    dataStructure = null, redeliveryCounter = 0, size = 0, properties = {timestamp=1599636300958}, 
   readOnlyProperties = true, readOnlyBody = true, droppable = false, 
   jmsXGroupFirstForConsumer = false}

不必去指定type维护队列的信息关系，获取

destination = queue: //add_xxxxxx,

即获取originalDestination属性，判断此消息的入队队列是哪个，然后获取该队列的消费者入队消息进行转换

这个方法是肯定能监听到死信队列的，亲测有效。

(1) 死信队列的配置（一般采用默认）

1. sharedDeadLetterStrategy

不管是queue还是topic，失败的消息都放到这个队列中。下面修改activemq.xml的配置，可以达到修改队列的名字。

2. individualDeadLetterStrategy

可以为queue和topic单独指定两个死信队列。还可以为某个话题，单独指定一个死信队列。

activemq的API文档 http://activemq.apache.org/maven/apidocs/index.html