JBoss EJB3(Message Driven Beans)備忘記

import javax.annotation.PreDestroy;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;
@MessageDriven(activationConfig = {
@ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Topic"),
@ActivationConfigProperty(propertyName = "destination", propertyValue = "topic/jms/HelloWorldMdbTopic")
})
// MessageDriven 定義這 class 為 Mesasge Driven Beans, 必須繼承 MessageListener
// destinationType 定義使用 javax.jms.Topic, 如果是 queue 則使用 javax.jms.Queue
// destination 定義 目的地 是 topic/jms/HelloWorldMdbTopic
public class HelloWorldMdbBean implements MessageListener {

public HelloWorldMdbBean(){
System.out.println("Local Server initialized on HelloWorldMdbBean...");
}

public void onMessage(Message msg) { // 這是 MessageListener 裡必須實作的 method,
if (msg instanceof TextMessage) {
TextMessage tm = (TextMessage) msg; // 這裡將 Message 轉換成 TextMessage
try {
String text = tm.getText();
System.out.println("Local Server HelloWorldMdbBean received message : " + text);
} catch (JMSException e) {
e.printStackTrace();
}
}
}

@PreDestroy // 為 callback method, 當 instance 消除前呼叫這函數
public void remove() {
System.out.println("Local Server HelloWorldMdbBean destroyed.");
}
}
/*------------------- HelloWorldMdbBean.java -----------------*/

[5] 建立 Client 端 Consumer：
/*------------------- HelloWorldConsumerClient.java -----------------*/
package ejb3.joeyta.clients;

import java.util.Properties;

import javax.annotation.PreDestroy;
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.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.naming.InitialContext;

public class HelloWorldConsumerClient implements MessageListener {

public static void main(String[] args) throws Exception {
new HelloWorldConsumerClient();
}

public static InitialContext getInitialContext()
throws javax.naming.NamingException {

Properties p = new Properties();
p.put(InitialContext.INITIAL_CONTEXT_FACTORY,
"org.jnp.interfaces.NamingContextFactory");
p.put(InitialContext.URL_PKG_PREFIXES,
" org.jboss.naming:org.jnp.interfaces");
p.put(InitialContext.PROVIDER_URL, "jnp://localhost:1099");
return new javax.naming.InitialContext(p);
}

public HelloWorldConsumerClient() throws Exception {
InitialContext jndiContext = getInitialContext(); // 初始化 JNDI

ConnectionFactory factory = (ConnectionFactory) jndiContext.lookup("ConnectionFactory");
// 1: 尋找 connection factory

Connection connect = factory.createConnection();
// 2: 以 connection factory 建立 JMD connection

Session session = connect.createSession(false, Session.AUTO_ACKNOWLEDGE);
// 3: 以 connection 建立 session, false 表示不使用 transaction,
// Session.AUTO_ACKNOWLEDGE 為設定怎樣確定接收 message,

Topic topic = (Topic) jndiContext.lookup("topic/jms/HelloWorldMdbTopic");
// 4: 尋找 destination, 如果是 queue, 這裡只需將 topic 改成 queue, Topic 改成 Queue.

MessageConsumer consumer = session.createConsumer(topic);
// 5: 建立 message consumer

consumer.setMessageListener(this);
// 將這個 Class 加入到 MessageListener 裡

System.out.println("Remote Client listening for messages on HelloWorldConsumerClient...");
connect.start(); // 開始連結
}

public void onMessage(Message msg) {
if (msg instanceof TextMessage) {
TextMessage tm = (TextMessage) msg; // 這裡將 Message 轉換成 TextMessage
try {
String text = tm.getText();
System.out.println("Remote Client HelloWorldConsumerClient received message : " + text);
} catch (JMSException e) {
e.printStackTrace();
}
}
}

@PreDestroy // 為 callback method, 當 instance 消除前呼叫這函數
public void remove() {
System.out.println("Remote Client HelloWorldConsumerClient destroyed.");
}
}
/*------------------- HelloWorldConsumerClient.java -----------------*/
由於這次實作使用 Topic,
故 Remote Client 及 Local server 端均可接收 message.
如果使用的是 Queue, 則最後註冊 Listener 才能收到 message.

[6] 建立 Client 端 Producer：
/*------------------- HelloWorldProducerClient.java -----------------*/
package ejb3.joeyta.clients;

import java.util.Properties;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.naming.InitialContext;

public class HelloWorldProducerClient {
public static InitialContext getInitialContext()
throws javax.naming.NamingException {

Properties p = new Properties();
p.put(InitialContext.INITIAL_CONTEXT_FACTORY,
"org.jnp.interfaces.NamingContextFactory");
p.put(InitialContext.URL_PKG_PREFIXES,
" org.jboss.naming:org.jnp.interfaces");
p.put(InitialContext.PROVIDER_URL, "jnp://localhost:1099");
return new javax.naming.InitialContext(p);
}

public static void main(String[] args) throws Exception {
InitialContext ctx = getInitialContext(); // 初始化 JNDI

ConnectionFactory factory = (ConnectionFactory) ctx.lookup("ConnectionFactory");
// 1: 尋找 connection factory

Connection connection = factory.createConnection();
// 2: 以 connection factory 建立 JMD connection

Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);
// 3: 以 connection 建立 session, false 表示不使用 transaction,
// Session.AUTO_ACKNOWLEDGE 為設定怎樣確定接收 message, 這 client 為發送, 故不重要

Topic topic = (Topic) ctx.lookup("topic/jms/HelloWorldMdbTopic");
// 4: 尋找 destination, 如果是 queue, 這裡只需將 topic 改成 queue, Topic 改成 Queue.
// Message Driven Bean 當然也要修改.

MessageProducer producer = session.createProducer(topic);
// 5: 建立 message producer

TextMessage msg = session.createTextMessage();
msg.setText("Joeyta try HelloWorld Message Driven Beans.");
producer.send(msg);
// 6: 上面三句建立及發送 message

producer.close(); // 關閉 producer
System.out.println("Message produced.");
}
}
/*------------------- HelloWorldProducerClient.java -----------------*/

項目結構如下圖所示：



[7] 使用 ANT 建立 EJB-JAR 並執行 Client 程式：