activeMQ文件传输

ActiveMQ之三 -- 使用ActiveMQ来传送文件

博客分类：  Java Component

 

这个方法还有待研究，目前还有如下几个疑点： 
1. ActiveMQ 报出这样的信息：

 INFO | Usage Manager memory limit (1048576) reached for topic://EXCHANGE.FILE. Producers will be throttled to the rate at which messages are removed from this
 destination to prevent flooding it. See http://activemq.apache.org/producer-flow-control.html for more info

 

2. 这种以异步方式传送资料，能保证客户端能以正确的顺序接收到文件段麽？

 

使用ActiveMQ传送文件，发送端必须将文件拆成一段一段，每段封装在独立的Message中，逐次发送到客户端。例如下面的例子，Producer通过发送命令，告诉文件传送的开始，发送中，结束。客户端接收到这些命令之后，就知道如何接收资料了。

客户端收到内容后，根据命令将内容合并到一个文件中。  

 

 package org.apache.activemq.exchange.file;

 import java.io.BufferedOutputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;

 import javax.jms.Connection;
 import javax.jms.ConnectionFactory;
 import javax.jms.Destination;
 import javax.jms.JMSException;
 import javax.jms.Message;
 import javax.jms.MessageConsumer;
 import javax.jms.Session;
 import javax.jms.StreamMessage;

 import org.apache.activemq.ActiveMQConnectionFactory;

 public class Consumer {

     /**
      * @param args
      */
     public static void main(String[] args) throws JMSException, IOException {
         ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616");

         Connection connection = factory.createConnection();
         connection.start();

         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

         Destination destination = session.createTopic("EXCHANGE.FILE");

         MessageConsumer consumer = session.createConsumer(destination);

         boolean appended = false;
         try {
             while (true) {
                 Message message = consumer.receive(5000);
                 if (message == null) {
                     continue;
                 }

                 if (message instanceof StreamMessage) {
                     StreamMessage streamMessage = (StreamMessage) message;
                     String command = streamMessage.getStringProperty("COMMAND");

                     if ("start".equals(command)) {
                         appended = false;
                         continue;
                     }

                     if ("sending".equals(command)) {
                         byte[] content = new byte[4096];
                         String file_name = message.getStringProperty("FILE_NAME");
                         BufferedOutputStream bos = null;
                         bos = new BufferedOutputStream(new FileOutputStream("c:/" + file_name, appended));
                         if (!appended) {
                             appended = true;
                         }
                         while (streamMessage.readBytes(content) > 0) {
                             bos.write(content);
                         }
                         bos.close();
                         continue;
                     }

                     if ("end".equals(command)) {
                         appended = false;
                         continue;
                     }
                 }
             }
         } catch (JMSException e) {
             throw e;
         } finally {
             if (connection != null) {
                 connection.close();
             }
         }

     }

 }

 

发送端将文件分包，逐次发送到客户端  

 package org.apache.activemq.exchange.file;

 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;

 import javax.jms.Connection;
 import javax.jms.ConnectionFactory;
 import javax.jms.Destination;
 import javax.jms.JMSException;
 import javax.jms.MessageProducer;
 import javax.jms.Session;
 import javax.jms.StreamMessage;

 import org.apache.activemq.ActiveMQConnectionFactory;

 public class Publisher {

     public static String FILE_NAME = "01.mp3";

     public static void main(String[] args) throws JMSException, IOException {
         ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616");
         Connection connection = factory.createConnection();
         connection.start();
         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
         Destination destination = session.createTopic("EXCHANGE.FILE");
         MessageProducer producer = session.createProducer(destination);
         long time = System.currentTimeMillis();

         //通知客户端开始接受文件
         StreamMessage message = session.createStreamMessage();
         message.setStringProperty("COMMAND", "start");
         producer.send(message);

         //开始发送文件
         byte[] content = new byte[4096];
         InputStream ins = Publisher.class.getResourceAsStream(FILE_NAME);
         BufferedInputStream bins = new BufferedInputStream(ins);
         while (bins.read(content) > 0) {
             //
             message = session.createStreamMessage();
             message.setStringProperty("FILE_NAME", FILE_NAME);
             message.setStringProperty("COMMAND", "sending");
             message.clearBody();
             message.writeBytes(content);
             producer.send(message);
         }
         bins.close();
         ins.close();

         //通知客户端发送完毕
         message = session.createStreamMessage();
         message.setStringProperty("COMMAND", "end");
         producer.send(message);

         connection.close();

         System.out.println("Total Time costed : " + (System.currentTimeMillis() - time) + " mili seconds");
     }
 }