在使用JSF 2和Ajax的简单演示Web应用程序中,ManagedBean中有一个方法从JMS队列接收消息:
@ManagedBean
public class Bean {
@Resource(mappedName = "jms/HabariConnectionFactory")
private ConnectionFactory connectionFactory;
@Resource(mappedName = "jms/TOOL.DEFAULT")
private Queue queue;
public String getMessage() {
String result = "no message";
try {
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
MessageConsumer consumer = session.createConsumer(queue);
Message message = consumer.receiveNoWait();
if (message != null) {
result = ((TextMessage) message).getText();
}
connection.close();
} catch (JMSException ex) {
Logger.getLogger(Bean.class.getName()).log(Level.SEVERE, null, ex);
}
return result;
}
}
每次调用getMessage()方法时都会打开/关闭JMS连接.在bean生命周期中,我只需要打开和关闭JMS连接一次,以避免频繁的连接/断开操作?
最佳答案 首先,将Connection移动为实例变量,以便可以从open,close和getMessage方法访问它.
接下来,使用PostConstruct注释创建openConnection方法.
@PostConstruct
public void openConnection() {
connection = connectionFactory.createConnection();
}
最后,使用PreDestroy注释创建一个closeConnection方法.
@PreDestroy
public void closeConnection() {
connection.close();
}