ActiveMQ之P2P点对点通信方式

水深无声 2022-09-25 00:20 218阅读 0赞

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61616
    		connection = 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pubsub
    		System.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61616
    		connection = 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pubsub
    		publisher.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~