ActiveMQ入门示例

企业中各项目中相互协作的时候可能用得到消息通知机制。比如有东西更新了，可以通知做索引。

在 Java 里有 JMS 的多个实现。其中 apache 下的 ActiveMQ 就是不错的选择。ActiveMQ 是Apache出品，最流行的，能力强劲的开源消息总线。ActiveMQ 是一个完全支持JMS1.1和J2EE 1.4规范的 JMS Provider实现。这里示例下使用 ActiveMQ

用 ActiveMQ 最好还是了解下 JMS

JMS 公共	点对点域	发布/订阅域
ConnectionFactory	QueueConnectionFactory	TopicConnectionFactory
Connection	QueueConnection	TopicConnection
Destination	Queue	Topic
Session	QueueSession	TopicSession
MessageProducer	QueueSender	TopicPublisher
MessageConsumer	QueueReceiver	TopicSubscriber

JMS 定义了两种方式：Quere（点对点）；Topic（发布/订阅）。

ConnectionFactory 是连接工厂，负责创建Connection。

Connection 负责创建 Session。

Session 创建 MessageProducer（用来发消息） 和 MessageConsumer（用来接收消息）。

Destination 是消息的目的地。

详细的可以网上找些 JMS 规范（有中文版）。

下载 apache-activemq-5.3.0。http://activemq.apache.org/download.html ，解压，然后双击 bin/activemq.bat。运行后，可以在 http://localhost:8161/admin 观察。也有 demo， http://localhost:8161/demo 。把 activemq-all-5.3.0.jar 加入 classpath。

Jms 发送 代码：

public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(); Connection connection = connectionFactory.createConnection(); connection.start(); Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE); Destination destination = session.createQueue("my-queue"); MessageProducer producer = session.createProducer(destination); for(int i=0; i<3; i++) { MapMessage message = session.createMapMessage(); message.setLong("count", new Date().getTime()); Thread.sleep(1000); //通过消息生产者发出消息 producer.send(message); } session.commit(); session.close(); connection.close(); }

 

Jms 接收代码：

public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(); Connection connection = connectionFactory.createConnection(); connection.start(); final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE); Destination destination = session.createQueue("my-queue"); MessageConsumer consumer = session.createConsumer(destination); int i=0; while(i<3) { i++; MapMessage message = (MapMessage) consumer.receive(); session.commit(); //TODO something.... System.out.println("收到消息：" + new Date(message.getLong("count"))); } session.close(); connection.close(); }

 

 

 

JMS五种消息的发送/接收的例子

转自：http://chenjumin.javaeye.com/blog/687124  

1、消息发送

//连接工厂 ConnectionFactory connFactory = new ActiveMQConnectionFactory( ActiveMQConnection.DEFAULT_USER, ActiveMQConnection.DEFAULT_PASSWORD, "tcp://localhost:61616"); //连接到JMS提供者 Connection conn = connFactory.createConnection(); conn.start(); //事务性会话，自动确认消息 Session session = conn.createSession(true, Session.AUTO_ACKNOWLEDGE); //消息的目的地 Destination destination = session.createQueue("queue.hello"); //消息生产者 MessageProducer producer = session.createProducer(destination); producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT); //不持久化 //文本消息 TextMessage textMessage = session.createTextMessage("文本消息"); producer.send(textMessage); //键值对消息 MapMessage mapMessage = session.createMapMessage(); mapMessage.setLong("age", new Long(32)); mapMessage.setDouble("sarray", new Double(5867.15)); mapMessage.setString("username", "键值对消息"); producer.send(mapMessage); //流消息 StreamMessage streamMessage = session.createStreamMessage(); streamMessage.writeString("streamMessage流消息"); streamMessage.writeLong(55); producer.send(streamMessage); //字节消息 String s = "BytesMessage字节消息"; BytesMessage bytesMessage = session.createBytesMessage(); bytesMessage.writeBytes(s.getBytes()); producer.send(bytesMessage); //对象消息 User user = new User("cjm", "对象消息"); //User对象必须实现Serializable接口 ObjectMessage objectMessage = session.createObjectMessage(); objectMessage.setObject(user); producer.send(objectMessage); session.commit(); //在事务性会话中，只有commit之后，消息才会真正到达目的地 producer.close(); session.close(); conn.close();

2、消息接收：通过消息监听器的方式接收消息

public class Receiver implements MessageListener{ private boolean stop = false; public void execute() throws Exception { //连接工厂 ConnectionFactory connFactory = new ActiveMQConnectionFactory( ActiveMQConnection.DEFAULT_USER, ActiveMQConnection.DEFAULT_PASSWORD, "tcp://localhost:61616"); //连接到JMS提供者 Connection conn = connFactory.createConnection(); conn.start(); //事务性会话，自动确认消息 Session session = conn.createSession(true, Session.AUTO_ACKNOWLEDGE); //消息的来源地 Destination destination = session.createQueue("queue.hello"); //消息消费者 MessageConsumer consumer = session.createConsumer(destination); consumer.setMessageListener(this); //等待接收消息 while(!stop){ Thread.sleep(5000); } session.commit(); consumer.close(); session.close(); conn.close(); } public void onMessage(Message m) { try{ if(m instanceof TextMessage){ //接收文本消息 TextMessage message = (TextMessage)m; System.out.println(message.getText()); }else if(m instanceof MapMessage){ //接收键值对消息 MapMessage message = (MapMessage)m; System.out.println(message.getLong("age")); System.out.println(message.getDouble("sarray")); System.out.println(message.getString("username")); }else if(m instanceof StreamMessage){ //接收流消息 StreamMessage message = (StreamMessage)m; System.out.println(message.readString()); System.out.println(message.readLong()); }else if(m instanceof BytesMessage){ //接收字节消息 byte[] b = new byte[1024]; int len = -1; BytesMessage message = (BytesMessage)m; while((len=message.readBytes(b))!=-1){ System.out.println(new String(b, 0, len)); } }else if(m instanceof ObjectMessage){ //接收对象消息 ObjectMessage message = (ObjectMessage)m; User user = (User)message.getObject(); System.out.println(user.getUsername() + " _ " + user.getPassword()); }else{ System.out.println(m); } stop = true; }catch(JMSException e){ stop = true; e.printStackTrace(); } } }