Question

我尝试使用TopicBrowser浏览主题中的邮件。要调用将返回createBrowser对象的正确TopicBrowser方法，我需要将topicSession变量投射到AQjmsSession。

private InitialContext initialContext;
private TopicConnection topicConnection;
private TopicSession topicSession;
private Topic topic;

private TopicConnectionFactory topicFactory;

private TextMessage message;

private void initTopic(Context context, String topicName) throws NamingException, JMSException {
    System.out.println("initializing the queue...");
    topicFactory = (TopicConnectionFactory) context.lookup(JMS_FACTORY);
    topicConnection = topicFactory.createTopicConnection();

    //queueConnection.setExceptionListener(this);
    topicSession = topicConnection.createTopicSession(false, Session.AUTO_ACKNOWLEDGE);
    System.out.println("session created, lookup queue: " + topicName);

    topic = (Topic)context.lookup(topicName);
    System.out.println("done...");
}

private void readTopicMessage() throws JMSException {
    int counter = 0;
    System.out.println("Starting the subscriber");
    TopicBrowser topicBrowser = ((AQjmsSession) topicSession).createBrowser(topic, SUBSCRIBER);
    Enumeration msgs = topicBrowser.getEnumeration();
    //topicConnection.start();
    System.out.println("Topic started\n");
    if (!msgs.hasMoreElements()) {
        System.out.println("No messages in topic");
    } else {
        while (msgs.hasMoreElements()) {
            System.out.println(">>> message count: " + ++counter);

            Message message = (Message) msgs.nextElement();
            System.out.println("MessageID: " + message.getJMSMessageID() + "\tPriority: " + message.getJMSPriority() + "\tDeliveryMode: " + message.getJMSDeliveryMode());
            System.out.println("Timestamp: " + message.getJMSTimestamp() + "\tJMSDestination: " + message.getJMSDestination() + "\tReplyTo: " + message.getJMSReplyTo());
            if (message instanceof TextMessage)
                System.out.println("Data: " + ((TextMessage) message).getText());

            System.out.println("\n");

            if (counter >= 5) break;
        }
    }

    System.out.println("stopping the topic");
    topicConnection.stop();
}

尝试进行此演员会给我这个错误：

java.lang.ClassCastException: weblogic.jms.client.WLSessionImpl cannot be cast to oracle.jms.AQjmsSession

Answer 1

您无法将其强制转换为该类型，因为您的应用程序所使用的客户端并非来自您认为的提供程序。根据例外情况，TopicSession是WebLogic JMS客户端提供的类型，因此强制转换注定会失败。您应该查看您的JNDI配置，看看它是否按照您认为配置的方式进行配置。

您的JNDI属性告诉代码从哪里创建ConnectionFactory并且获取WebLogic客户端位，您似乎需要Oracle AQ位，因此在JNDI步骤中查找的ConnectionFactory需要是Oracle的。

无法将JMS TopicSession转换为AQjmsSession

1 个答案: