ActiveMQ的消息过滤器

1、消息过滤器的简介

      消息选择器的用法
      MessageConsumer是一个Session创建的对象，用来从Destination接收消息

      关于消息选择器
      MessageConsumer createConsumer( Destination destination, String messageSelector )
      MessageConsumer createConsumer( Destination destination, String messageSelector, boolean noLocal )

      其中，messageSelector为消息选择器； 
      noLocal标志默认为false，当设置为true时，限制消费者只能接收和自己相同的连接(Connection)所发布的消息，此标志只适用于主题，不适用于队列。

      public final String SELECTOR="JMS_TYPE='MY_TAG1'" ; 
      选择器检查传入消息的JMS_TYPE的属性，并确定这个属性的值是否等于MY_TAG1；
      如果相等，消息报消费；如果不相等，那么消息就会被忽略；

2、Producer.java的代码

import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.DeliveryMode;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MapMessage;import javax.jms.MessageProducer;import javax.jms.Session;import javax.jms.TextMessage;import org.apache.activemq.ActiveMQConnectionFactory;public class Producer {// 单例模式// 1、连接工厂private ConnectionFactory connectionFactory;// 2、连接对象private Connection connection;// 3、Session对象private Session session;// 4、生产者private MessageProducer messageProducer;public Producer() {try {this.connectionFactory = new ActiveMQConnectionFactory("zhangsan","123", "tcp://localhost:61616");this.connection = connectionFactory.createConnection();this.connection.start();// 设置自动签收模式this.session = this.connection.createSession(false,Session.AUTO_ACKNOWLEDGE);this.messageProducer = this.session.createProducer(null);} catch (JMSException e) {throw new RuntimeException(e);}}public Session getSession() {return this.session;}public void send1(/* String QueueName, Message message */) {try {Destination destination = this.session.createQueue("first");MapMessage msg1 = this.session.createMapMessage();msg1.setString("name", "张三");msg1.setInt("age", 20);// 设置用于消息过滤器的条件msg1.setStringProperty("name", "张三");msg1.setIntProperty("age", 20);msg1.setStringProperty("color", "bule");MapMessage msg2 = this.session.createMapMessage();msg2.setString("name", "李四");msg2.setInt("age", 25);// 设置用于消息过滤器的条件msg2.setStringProperty("name", "李四");msg2.setIntProperty("age", 25);msg2.setStringProperty("color", "white");MapMessage msg3 = this.session.createMapMessage();msg3.setString("name", "张三");msg3.setInt("age", 30);// 设置用于消息过滤器的条件msg3.setStringProperty("name", "赵六");msg3.setIntProperty("age", 30);msg3.setStringProperty("color", "black");// 发送消息this.messageProducer.send(destination, msg1,DeliveryMode.NON_PERSISTENT, 4, 1000 * 60 * 10);this.messageProducer.send(destination, msg2,DeliveryMode.NON_PERSISTENT, 4, 1000 * 60 * 10);this.messageProducer.send(destination, msg3,DeliveryMode.NON_PERSISTENT, 4, 1000 * 60 * 10);} catch (JMSException e) {throw new RuntimeException(e);}}public void send2() {try {Destination destination = this.session.createQueue("first");TextMessage message = this.session.createTextMessage("我是一个字符串");// 发送消息this.messageProducer.send(destination, message,DeliveryMode.NON_PERSISTENT, 4, 1000 * 60 * 10);} catch (JMSException e) {throw new RuntimeException(e);}}public static void main(String[] args) {Producer producer = new Producer();producer.send1();}}

3、Conmuser.java的代码

import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MapMessage;import javax.jms.Message;import javax.jms.MessageConsumer;import javax.jms.MessageListener;import javax.jms.Session;import javax.jms.TextMessage;import org.apache.activemq.ActiveMQConnectionFactory;public class Conmuser {// 单例模式// 1、连接工厂private ConnectionFactory connectionFactory;// 2、连接对象private Connection connection;// 3、Session对象private Session session;// 4、生产者private MessageConsumer messageConsumer;// 5、目的地址private Destination destination;// 消息选择器public final String SELECTOR_1 = "age > 20";public Conmuser() {try {this.connectionFactory = new ActiveMQConnectionFactory("zhangsan","123", "tcp://localhost:61616");this.connection = connectionFactory.createConnection();this.connection.start();// 设置自动签收模式this.session = this.connection.createSession(false,Session.AUTO_ACKNOWLEDGE);this.destination = this.session.createQueue("first");// 在构造消费者的时候，指定了 消息选择器// 有选择性的消费消息this.messageConsumer = this.session.createConsumer(destination,SELECTOR_1);} catch (JMSException e) {throw new RuntimeException(e);}}public Session getSession() {return this.session;}// 用于监听消息队列的消息class MyLister implements MessageListener {@Overridepublic void onMessage(Message message) {try {if (message instanceof TextMessage) {}if (message instanceof MapMessage) {MapMessage ret = (MapMessage) message;System.out.println(ret.toString());System.out.println(ret.getString("name"));System.out.println(ret.getInt("age"));}} catch (JMSException e) {throw new RuntimeException(e);}}}// 用于异步监听消息public void receiver() {try {this.messageConsumer.setMessageListener(new MyLister());} catch (JMSException e) {throw new RuntimeException(e);}}public static void main(String[] args) {Conmuser conmuser = new Conmuser();conmuser.receiver();}}

4、需要注意的地方

      4.1  注意消息过滤器的过滤条件的设置

// 设置用于消息过滤器的条件msg3.setStringProperty("name", "赵六");msg3.setIntProperty("age", 30);msg3.setStringProperty("color", "black");

       

       4.2 消息过滤器的写法(类似于SQL语句的写法)

// 消息选择器public final String SELECTOR_1 = "age > 20";public final String SELECTOR_2 = " age > 20 and color='bule'";