JMS简谈
// Create a Message consumer by Session and Queue
MessageConsumer consumer = session.createConsumer(queue);
// There are 2 ways for the consumer to receive the message.
// 1. receive() and receive(timeout)
// 1.1: The consumer will wait forever until the message arrived
Message receiveMessage = consumer.receive();
// 1.2: If the consumer can't get the message in time, receiveMessage is empty, there?
// will be nullpointerException
// Message receiveMessage = consumer.receive(20000);
System.out.println("The First Consumer" + ((TextMessage)receiveMessage).getText());
// 2. register a message listener, if the message arrived, call its onMessage
consumer.setMessageListener(new MessageListener() {
public void onMessage(Message m) {
TextMessage textMsg = (TextMessage)m;
try {
System.out.println("The second consumer" +textMsg.getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
}
}
由前面的例子可以看出，消息的消费者接收消息可以采用两种方式：
? 1、consumer.receive() 或 consumer.receive(int timeout)；
? 2、注册一个MessageListener。
? 采用第一种方式，消息的接收者会一直等待下去，直到有消息到达，或者超时。后一种方式会注册一个监听器，当有消息到达的时候，会回调它的onMessage()方法。下面举例说明：
MessageConsumer comsumer = session.createConsumer(queue);
comsumer.setMessageListener(new MessageListener(){
??????????? @Override
??????????? public void onMessage(Message m) {
??????????????? TextMessage textMsg = (TextMessage) m;
??????????????? try {
??????????????????? System.out.println(textMsg.getText());
??????????????? } catch (JMSException e) {
??????????????????? e.printStackTrace();
??????????????? }
??????????? }
???????????
??????? });
Queue实现的是点到点模型，在下面的例子中，启动2个消费者共同监听一个Queue，然后循环给这个Queue中发送多个消息，我们依然采用ActiveMQ。
package basic;
import javax.jms.Connection;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
public class QueueTest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
// Create a Queue
Queue queue = new ActiveMQQueue("JoshQueue2");
// Create a session
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Register consumer 1
MessageConsumer consumer1 = session.createConsumer(queue);
consumer1.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println(" Consumer 1 get" + ((TextMessage)message).getText());
} catch (Exception e) {
e.printStackTrace();
}
}
});
// Register consumer 2
MessageConsumer consumer2 = session.createConsumer(queue);
consumer2.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println(" Consumer 2 get" + ((TextMessage)message).getText());
} catch (Exception e) {
e.printStackTrace();
}
}
});
// Create a producer, and send multiple messages
MessageProducer producer = session.createProducer(queue);
for (int i = 0; i < 10; i++) {
producer.send(session.createTextMessage("Message" + i));
}
// if close the session or connection quickly, you will see some message still
// have not received by the consumer.
// session.close();
// connection.close();
}
}
????与Queue不同的是，Topic实现的是发布/订阅模型，在下面的例子中，启动2个消费者共同监听一个Topic，然后循环给这个Topic中发送多个消息。
package basic;
import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQTopic;
public class TopicTest {
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
// Create a Topic
Topic topic = new ActiveMQTopic("joshTopic");
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// register consumer1
MessageConsumer consumer1 = session.createConsumer(topic);
consumer1.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Consumer1 get" + ((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
// register consumer2
MessageConsumer consumer2 = session.createConsumer(topic);
consumer2.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Consumer2 get" + ((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
// Create a producer, and send several messages
MessageProducer producer = session.createProducer(topic);
for (int i = 0; i < 10; i++) {
producer.send(session.createTextMessage("Message" + i));
}
}
}
????一个消息对象分为三部分：消息头(Headers)，属性（Properties）和消息体（Payload）。对于StreamMessage和 MapMessage，消息本身就有特定的结构，而对于TextMessage，ObjectMessage和BytesMessage是无结构的。一个 消息可以包含一些重要的数据或者仅仅是一个事件的通知。
??? 消息的Headers部分通常包含一些消息的描述信息，它们都是标准的描述信息。包含下面一些值：
JMSDestination
?????? 消息的目的地，Topic或者是Queue。
JMSDeliveryMode
??????? 消息的发送模式：persistent或nonpersistent。前者表示消息在被消费之前，如果JMS提供者DOWN了，重新启动后消息仍然存在。后者在这种情况下表示消息会被丢失。可以通过下面的方式设置：
?????? Producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
?????JMSTimestamp
?????? 当调用send()方法的时候，JMSTimestamp会被自动设置为当前事件。可以通过下面方式得到这个值：
?????? long timestamp = message.getJMSTimestamp();
JMSExpiration
?????? 表示一个消息的有效期。只有在这个有效期内，消息消费者才可以消费这个消息。默认值为0，表示消息永不过期。可以通过下面的方式设置：
?????? producer.setTimeToLive(3600000); //有效期1小时 （1000毫秒 * 60秒 * 60分）
JMSPriority
?????? 消息的优先级。0-4为正常的优先级，5-9为高优先级。可以通过下面方式设置：
?????? producer.setPriority(9);
JMSMessageID
?????? 一个字符串用来唯一标示一个消息。
JMSReplyTo
?????? 有时消息生产者希望消费者回复一个消息，JMSReplyTo为一个Destination，表示需要回复的目的地。当然消费者可以不理会它。
JMSCorrelationID
?????? 通常用来关联多个Message。例如需要回复一个消息，可以把JMSCorrelationID设置为所收到的消息的JMSMessageID。
JMSType
?????? 表示消息体的结构，和JMS提供者有关。
JMSRedelivered
?????? 如果这个值为true，表示消息是被重新发送了。因为有时消费者没有确认他已经收到消息或者JMS提供者不确定消费者是否已经收到。
??? 除了Header，消息发送者可以添加一些属性(Properties)。这些属性可以是应用自定义的属性，JMS定义的属性和JMS提供者定义的属性。我们通常只适用自定义的属性。
??? 后面会讲到这些Header和属性的用法。
?
（七）：DeliveryMode例子
??? 在下面的例子中，分别发送一个Persistent和nonpersistent的消息，然后关闭退出JMS。[/size]
/**
*?
*/
package deliverymode;
import javax.jms.Connection;
import javax.jms.DeliveryMode;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
* After run the application successfully, Stop JMS provider
* If the message is persistent, Even the JMS' provider done(ActiveMQ, EJB Message Driven Bean),
* After restart JMS' provider, the related consumer can get the message.
*
*/
public class DeliveryModeSendTest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
Queue queue = new ActiveMQQueue("JoshDeliveryModeQueue");
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageProducer producer = session.createProducer(queue);
producer.setDeliveryMode(DeliveryMode.PERSISTENT);
producer.send(session.createTextMessage("A Persistent Message"));
producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
producer.send(session.createTextMessage("A Non Persistent Message"));
System.out.println("Send messages Successfully!!!");
}
}
运行上面的程序，当输出“Send messages sucessfully!”时，说明两个消息都已经发送成功，然后我们结束它，来停止JMS Provider。
接下来我们重新启动JMS Provicer，然后添加一个消费者：
/**
*?
*/
package deliverymode;
import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
*
*/
public class DeliveryModeReceiveTest {
/**
* Run the application, there only one message: persistent message can be
* received successfully.
*?
* In addition to, when sending a non persistent message and there is no?
* any listener listen at the same time, the message will lost too.
*?
* @param args
*/
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
// The queues name must equals the queues name with the Producer queue
Queue queue = new ActiveMQQueue("JoshDeliveryModeQueue");
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageConsumer consumer = session.createConsumer(queue);
consumer.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Consumer get " + ((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
}
}
运行上面的程序，可以得到下面的输出结果：
Consumer get A persistent Message
可以看出消息消费者只接收到一个消息，它是一个Persistent的消息。而刚才发送的non persistent消息已经丢失了。
另外, 如果发送一个non persistent消息, 而刚好这个时候没有消费者在监听, 这个消息也会丢失.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? （八）：JMSReplyTo
在下面的例子中，首先创建两个Queue，发送者给一个Queue发送，接收者接收到消息之后给另一个Queue回复一个Message，然后再创建一个消费者来接受所回复的消息。[/size]
/**
*?
*/
package reply;
import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
* Producer send a message with the content "Josh", The receiver will reply
* to the message after received the message, the content is "Hello, Josh",?
* Finally create another consumer on the second queue and print the content.
*
*/
public class MessageSendReceiveAndReply {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
// Send the message to the queue
Queue queue = new ActiveMQQueue("Josh_ReceiveQueue");
// Reply the message to the queue
Queue replyQueue = new ActiveMQQueue("Josh_ReplyQueue");
final Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Create a message and set the JMSReplyTo with replyQueue
Message message = session.createTextMessage("Josh");
// Define where will the message reply to
message.setJMSReplyTo(replyQueue);?
MessageProducer producer = session.createProducer(queue);
producer.send(message);
// The receiver of the Message
MessageConsumer consumer = session.createConsumer(queue);
consumer.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Start to receive the message");
// Create a new Message Producer to send the reply message.
MessageProducer producer = session.createProducer(message
.getJMSReplyTo());
producer.send(session.createTextMessage("Hello"
+ ((TextMessage) message).getText()));
System.out.println("Consumer receive the message and reply sucessfully");
} catch (Exception e) {
e.printStackTrace();
}
}
});
// The receiver is used to receive the replied message
MessageConsumer consumer2 = session.createConsumer(replyQueue);
consumer2.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println(((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
}
}
??? 前面的例子中创建一个消息消费者使用的是:
????????? sesssion.createConsumer(destination)
? 另外，还提供了另一种方式：
??? sesssion.createConsumer(destination, selector)
? 这里selector是一个字符串，用来过滤消息。也就是说，这种方式可以创建一个可以只接收特定消息的一个消费者。Selector的格式是类似于SQL-92的一种语法。可以用来比较消息头信息和属性。
? 下面的例子中，创建两个消费者，共同监听同一个Queue，但是它们的Selector不同，然后创建一个消息生产者，来发送多个消息。
/**
*?
*/
package selector;
import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
*?
* Consumer only receive the message which interested.
*
*/
public class JMSSelectorTest {
public static void main(String[] args) throws Exception {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
Queue queue = new ActiveMQQueue("JoshSelectorQueue");
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// the consumer only receive the message which properties is receiver equals A
MessageConsumer consumerA = session.createConsumer(queue, "receiver = 'A'");
consumerA.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Consumer A get " + ((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
MessageConsumer consumerB = session.createConsumer(queue, "receiver = 'B'");
consumerB.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Consumer B get " + ((TextMessage)message).getText());
} catch (JMSException e) {
e.printStackTrace();
}
}
});
MessageProducer producer = session.createProducer(queue);
for (int i = 0; i < 10; i ++) {
String receiver = i % 3 == 0 ? "A" : "B";
TextMessage message = session.createTextMessage("Message: " + i + ", receiver: " + receiver);
message.setStringProperty("receiver", receiver);
producer.send(message);
}
}
}
???前面讲过JMSCorrelationID主要是用来关联多个Message，例如需要回复一个消息的时候，通常把回复的消息的 JMSCorrelationID设置为原来消息的ID。在下面这个例子中，创建了三个消息生产者A，B，C和三个消息消费者A，B，C。生产者A给消费 者A发送一个消息，同时需要消费者A给它回复一个消息。B、C与A类似。
??? 简图如下：
?????? 生产者A-----发送----〉消费者A-----回复------〉生产者A
??????? 生产者B-----发送----〉消费者B-----回复------〉生产者B
??????? 生产者C-----发送----〉消费者C-----回复------〉生产者C
???
??? 需要注意的是，所有的发送和回复都使用同一个Queue，通过Selector区分。
/**
*?
*/
package correlation;
import javax.jms.Connection;
import javax.jms.DeliveryMode;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
*
*/
public class JMSCorrelationTest {
private Queue queue;
private Session session;
public JMSCorrelationTest() throws JMSException {
ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
queue = new ActiveMQQueue("JoshCorrelationQueue");
session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
setupConsumer("ConsumerA");
??????? setupConsumer("ConsumerB");
??????? setupConsumer("ConsumerC");
???????
??????? setupProducer("ProducerA", "ConsumerA");
??????? setupProducer("ProducerB", "ConsumerB");
??????? setupProducer("ProducerC", "ConsumerC");
}
private void setupConsumer(final String name) throws JMSException {
// Create a receiver will receive its message
MessageConsumer consumer = session.createConsumer(queue, "receiver = '" + name +"'");
consumer.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
MessageProducer producer = session.createProducer(queue);
System.out.println(name + "get: " + ((TextMessage)message).getText());
// reply the message
Message replyMessage = session.createTextMessage("Reply from " + name);
// Set JMSCorrelationID is the receive message's Id
replyMessage.setJMSCorrelationID(message.getJMSMessageID());
// producer.send(message); // this will cause producer won't receive the reply message
producer.send(replyMessage);
} catch (JMSException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
private void setupProducer(final String name, String consumerName) throws JMSException {
MessageProducer producer = session.createProducer(queue);
producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
// Create a message and set a property:receiver with the value consumer name
Message message = session.createTextMessage("Message from: " + name);
message.setStringProperty("receiver", consumerName);
producer.send(message);
// wait the reply message
??????? MessageConsumer replyConsumer = session.createConsumer(queue, "JMSCorrelationID='" + message.getJMSMessageID() + "'");
??????? replyConsumer.setMessageListener(new MessageListener(){
??????????? public void onMessage(Message m) {
??????????????? try {
??????????????????? System.out.println(name + " get reply:" + ((TextMessage)m).getText());
??????????????? } catch (JMSException e) { }
??????????? }
??????? });
}
public static void main(String[] args) throws Exception {
new JMSCorrelationTest();
}
}
TemporaryQueue和TemporaryTopic，从字面上就可以看出它们是“临时”的目的地。可以通过Session来创建，例如：
??? TemporaryQueue replyQueue = session.createTemporaryQueue();
????
??? 虽然它们是由Session来创建的，但是它们的生命周期确实整个Connection。如果在一个Connection上创建了两个Session，则 一个Session创建的TemporaryQueue或TemporaryTopic也可以被另一个Session访问。那如果这两个Session是 由不同的Connection创建，则一个Session创建的TemporaryQueue不可以被另一个Session访问。
??? 另外，它们的主要作用就是用来指定回复目的地， 即作为JMSReplyTo。
??? 在下面的例子中，先创建一个Connection，然后创建两个Session，其中一个Session创建了一个TemporaryQueue，另一个Session在这个TemporaryQueue上读取消息。
/**
*?
*/
package temporary;
import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TemporaryQueue;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQQueue;
/**
*
*/
public class TemporaryQueueTest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
// ConnectionFactory provided by JMS' provider
ConnectionFactory factory = new ActiveMQConnectionFactory();
Connection connection = factory.createConnection();
connection.start();
// Destination provided by JMS' provider, either Queue or Topic
// Polymorphic, Queue provided by JMS' provider
Queue queue = new ActiveMQQueue("JoshQueue_permanent");
final Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Create a temporary queue by the session
TemporaryQueue replyQueue = session.createTemporaryQueue();
// receive the message and reply the message to specific queue(replyQueue)
MessageConsumer consumer = session.createConsumer(queue);
consumer.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Get Message: " + ((TextMessage)message).getText());
MessageProducer producer = session.createProducer(message.getJMSReplyTo());
producer.send(session.createTextMessage("ReplyMessage"));
} catch (JMSException e) {
e.printStackTrace();
}
}
});??
// Create another session by the same connection to read the replyQueue message
Session session2 = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageConsumer replyConsumer = session2.createConsumer(replyQueue);
replyConsumer.setMessageListener(new MessageListener() {
@Override
public void onMessage(Message message) {
try {
System.out.println("Get Reply: " +((TextMessage)message).getText());
} catch (JMSException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
MessageProducer producer = session.createProducer(queue);
TextMessage textMessage = session.createTextMessage("SimpleMessage");
textMessage.setJMSReplyTo(replyQueue);
producer.send(textMessage);
}
}
运行结果为：
Get Message: SimpleMessage
Get reply: ReplyMessage
如果将：
Session session2 = connection.createSession(true, Session.AUTO_ACKNOWLEDGE);
更改为：
Connection connection2 = factory.createConnection();
Session session2 = connection2.createSession(true, Session.AUTO_ACKNOWLEDGE);
就会得到类似于下面的异常：
Exception in thread "main" javax.jms.InvalidDestinationException: Cannot use a Temporary destination from another Connection。
在EJB3中，一个MDB（消息驱动Bean）就是一个实现了MessageListener接口的POJO。下面就是一个简单的MDB。
@MessageDriven(activationConfig={
??????? @ActivationConfigProperty(propertyName="destinationType",
??????????????? propertyValue="javax.jms.Queue"),
??????? @ActivationConfigProperty(propertyName="destination",
??????????????? propertyValue="queue/testQueue")})
public class SimpleMDB implements MessageListener {
???
??? public void onMessage(Message message) {
??????? try {
??????????? System.out.println("Receive Message : " + ((TextMessage)message).getText());
??????? } catch (JMSException e) {
??????????? e.printStackTrace();
??????? }
??? }
}
它要求必须标注为@MessageDriven。它所监听Destination通过标注属性来注入。
下面是一个发送消息的StatelessBean：
@Remote
public interface IMessageSender {
??? public void sendMessage(String content) throws Exception;
}
@Stateless
@Remote
public class MessageSender implements IMessageSender {
??? @Resource(mappedName="ConnectionFactory")
??? private ConnectionFactory factory;
???
??? @Resource(mappedName="queue/testQueue")
??? private Queue queue;
???
???
??? public void sendMessage(String content) throws Exception {
??????? Connection cn = factory.createConnection();
???????
??????? Session session = cn.createSession(false, Session.AUTO_ACKNOWLEDGE);
??????? MessageProducer producer = session.createProducer(queue);
??????? producer.send(session.createTextMessage(content));
??? }
}
这个EJB只有一个方法SendMessage。ConnectionFactory和Queue通过标注注入。
接下来是客户端：
public class MessageSenderClient {
??? public static void main(String[] args) throws Exception {
??????? Properties props = new Properties();
??????? props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory");
??????? props.setProperty(Context.PROVIDER_URL, "localhost:2099");
??????? Context context = new InitialContext(props);
??????? IMessageSender messageSender = (IMessageSender) context.lookup("MessageSender/remote");
??????? messageSender.sendMessage("Hello");
??? }
}
它通过JNDI查找到上面的EJB，然后调用sengMessage.
