ActiveMQ之P2P点对点通信方式

上一篇的代码是发布/订阅(PUS/SUB)的消息通信方式,发布者发布的一个主题,可以由多个消费者来订阅.

这一篇我们来介绍点对点(P2P)模型.P2P就好比两个人打电话,这两个人是独享这一条通信链路的,一方发送消息一方接收.

在p2p的场景里，相互通信的双方是通过一个类似于队列的方式来进行交流。和前面pub-sub的区别在于一个topic有一个发送者和多个接收者，而在p2p里一个queue只有一个发送者和一个接收者。

package activemqDemo02;import java.io.IOException;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.JMSException;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;/** * 消息消费者(consumer):它用于接收发送到目的地的消息 * @author licheng * */public class Consumer {public static final String url = "tcp://localhost:61616"; // 缺省端口,如果要改,可在apache-activemq-5.13.3\conf中的activemq.xml中更改端口号ConnectionFactory factory;Connection connection;Session session;MessageConsumer[] consumers;ComunicateMode comunicateMode = ComunicateMode.pubsub;enum ComunicateMode {p2p, pubsub}public Consumer(ComunicateMode mode, String[] destinationNames) throws JMSException{this.comunicateMode = mode;factory = new ActiveMQConnectionFactory(url); // 这里的url也可以不指定,java代码将默认将端口赋值为61616connection = factory.createConnection();connection.start();session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);consumers = new MessageConsumer[destinationNames.length];for (int i = 0; i < destinationNames.length; i++) {Destination destination = comunicateMode == ComunicateMode.pubsub ? session.createTopic("Topic." + destinationNames[i]) : session.createQueue("Queue." + destinationNames[i]);consumers[i] = session.createConsumer(destination);consumers[i].setMessageListener(new MessageListener(){public void onMessage(Message message) {try {System.out.println(String.format("收到消息[%s]", ((TextMessage) message).getText()));} catch (JMSException e) {e.printStackTrace();}}});}}public void close() throws JMSException {if(connection != null) {connection.close();}}public static void main(String[] args) throws JMSException, IOException {Consumer consumer = new Consumer(ComunicateMode.pubsub, new String[] {"2"}); // 这里可以修改消息传输方式为pubsubSystem.in.read();consumer.close();}}

package activemqDemo02;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.MessageProducer;import javax.jms.Session;import javax.jms.TextMessage;import org.apache.activemq.ActiveMQConnectionFactory;/** * 消息生产者(produceer):用于把消息发送到一个目的地 *  * @author licheng * */public class Publisher {public  static final  String url = "tcp://localhost:61616"; // 缺省端口,如果要改,可在apache-activemq-5.13.3\conf中的activemq.xml中更改端口号ConnectionFactory factory;Connection connection;Session session;MessageProducer producer;Destination[] destinations;ComunicateMode comunicateMode = ComunicateMode.pubsub;enum ComunicateMode {p2p, pubsub}public Publisher(ComunicateMode mode) throws JMSException {this.comunicateMode = mode;factory = new ActiveMQConnectionFactory(url); // 这里的url也可以不指定,java代码将默认将端口赋值为61616connection = factory.createConnection();try {connection.start();} catch (JMSException e) {connection.close();throw e;}session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);producer = session.createProducer(null);}protected void setDestinations(String[] stocks) throws JMSException {destinations = new Destination[stocks.length];for(int i = 0; i < stocks.length; i++) {destinations[i] = comunicateMode == ComunicateMode.pubsub ? session.createTopic("Topic." + stocks[i]) : session.createQueue("Queue." + stocks[i]);}}protected void sendMessage(String msg) throws JMSException {for (Destination item : destinations) {TextMessage msgMessage = session.createTextMessage(msg);producer.send(item, msgMessage);System.out.println(String.format("成功向Topic为[%s]发送消息[%s]", item.toString(), msgMessage.getText()));}}protected void close() throws JMSException {if(connection != null) {connection.close();}}public static void main(String[] args) throws JMSException, InterruptedException, IOException {Publisher publisher = new Publisher(ComunicateMode.pubsub); // 这里可以修改消息传输方式为pubsubpublisher.setDestinations(new String[] {"1","2","3"});BufferedReader reader = null;String contentString = "";do {System.out.println("请输入要发送的内容(exit退出)");reader = new BufferedReader(new InputStreamReader(System.in));contentString = reader.readLine();if(contentString.equals("exit")) {break;}publisher.sendMessage(contentString);} while (!contentString.equals("exit"));reader.close();publisher.close();}}

先开启activemq.bat,然后运行Consumer,再运行Publisher就可以了.队列和主题在代码里体现的区别在于,一个是创建消息队列,一个是创建消息主题.好困啊~