simpleasynchconsumer.java

《j2ee经典实例详解》的源代码。原书无附带光盘。介绍的是一个在线银行系统的例子。绝对难得

/*
 * Copyright (c) 2005 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2005 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */



/**
 * The SimpleAsynchConsumer class consists only of a main
 * method, which receives one or more messages from a queue or
 * topic using asynchronous message delivery.  It uses the
 * message listener TextListener.  Run this program in
 * conjunction with SimpleProducer.
 *
 * Specify a queue or topic name on the command line when you run
 * the program. To end the program, type Q or q on the command
 * line.
 */
import javax.jms.*;
import javax.naming.*;
import java.io.*;


public class SimpleAsynchConsumer {
    /**
     * Main method.
     *
     * @param args     the destination name and type used by the
     *                 example
     */
    public static void main(String[] args) {
        String destName = null;
        Context jndiContext = null;
        ConnectionFactory connectionFactory = null;
        Connection connection = null;
        Session session = null;
        Destination dest = null;
        MessageConsumer consumer = null;
        TextListener listener = null;
        TextMessage message = null;
        InputStreamReader inputStreamReader = null;
        char answer = '\0';

        if (args.length != 1) {
            System.out.println("Program takes one argument: <dest_name>");
            System.exit(1);
        }

        destName = new String(args[0]);
        System.out.println("Destination name is " + destName);

        /*
         * Create a JNDI API InitialContext object if none exists
         * yet.
         */
        try {
            jndiContext = new InitialContext();
        } catch (NamingException e) {
            System.out.println("Could not create JNDI API context: " +
                e.toString());
            System.exit(1);
        }

        /*
         * Look up connection factory and destination.  If either
         * does not exist, exit.  If you look up a
         * TopicConnectionFactory or a QueueConnectionFactory,
         * program behavior is the same.
         */
        try {
            connectionFactory =
                (ConnectionFactory) jndiContext.lookup("jms/ConnectionFactory");
            dest = (Destination) jndiContext.lookup(destName);
        } catch (Exception e) {
            System.out.println("JNDI API lookup failed: " + e.toString());
            System.exit(1);
        }

        /*
         * Create connection.
         * Create session from connection; false means session is
         * not transacted.
         * Create consumer.
         * Register message listener (TextListener).
         * Receive text messages from destination.
         * When all messages have been received, type Q to quit.
         * Close connection.
         */
        try {
            connection = connectionFactory.createConnection();
            session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            consumer = session.createConsumer(dest);
            listener = new TextListener();
            consumer.setMessageListener(listener);
            connection.start();
            System.out.println("To end program, type Q or q, " +
                "then <return>");
            inputStreamReader = new InputStreamReader(System.in);

            while (!((answer == 'q') || (answer == 'Q'))) {
                try {
                    answer = (char) inputStreamReader.read();
                } catch (IOException e) {
                    System.out.println("I/O exception: " + e.toString());
                }
            }
        } catch (JMSException e) {
            System.out.println("Exception occurred: " + e.toString());
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (JMSException e) {
                }
            }
        }
    }
}