ActiveMQ之二--JMS消息类型

1.前言

//发送文本消息
 session.createTextMessage(msg);

//接受文本消息
 public void onMessage(Message msg) {
    TextMessage message = (TextMessage) msg;
      ……
 }

根据Message接口的方法，可以获取消息类型

String msgType = getJMSType()

根据 JSR 914: JavaTM Message Service (JMS) API ，JMS规范中的消息类型包括TextMessage、BytesMessage、MapMessage、StreamMessage和ObjectMessage 等五种。ActiveMQ也有对应的实现，下面我们结合Spring JMS分别来看一下五种消息类型的收发代码。

2. 消息发送示例代码

/**
   * 向默认队列发送text消息
   */
  public void sendMessage(final String msg) {
    String destination = jmsTemplate.getDefaultDestination().toString();
    System.out.println("ProducerService向队列" + destination + "发送了消息：\t" + msg);
    jmsTemplate.send(new MessageCreator() {
      public Message createMessage(Session session) throws JMSException {
        return session.createTextMessage(msg);
      }
    });
  }

  /**
   * 向默认队列发送map消息
   */
  public void sendMapMessage() {
    jmsTemplate.send(new MessageCreator() {
      public Message createMessage(Session session) throws JMSException {
        MapMessage message = session.createMapMessage();
        message.setString("name", "小西山");
        return message;
      }
    });
  }

  /**
   * 向默认队列发送Object消息
   */
  public void sendObjectMessage() {
    jmsTemplate.send(new MessageCreator() {
      public Message createMessage(Session session) throws JMSException {
        Staff staff = new Staff(1, "搬砖工"); // Staff必须实现序列化
        ObjectMessage message = session.createObjectMessage(staff);
        return message;
      }
    });
  }

  /**
   * 向默认队列发送Bytes消息
   */
  public void sendBytesMessage() {
    jmsTemplate.send(new MessageCreator() {
      public Message createMessage(Session session) throws JMSException {
        String str = "BytesMessage 字节消息";
        BytesMessage message = session.createBytesMessage();
        message.writeBytes(str.getBytes());
        return message;
      }
    });
  }

  /**
   * 向默认队列发送Stream消息
   */
  public void sendStreamMessage() {
    jmsTemplate.send(new MessageCreator() {
      public Message createMessage(Session session) throws JMSException {
        String str = "StreamMessage 流消息";
        StreamMessage message = session.createStreamMessage();
        message.writeString(str);
        message.writeInt(521);
        return message;
      }
    });
  }

3.消息接受示例代码

  /**
   * 接受消息
   */
  public void receive(Destination destination) throws JMSException {
    Message message = jmsTemplate.receive(destination);
    // 如果是文本消息
    if (message instanceof TextMessage) {
      TextMessage tm = (TextMessage) message;
      System.out.println("ConsumerService从队列" + destination.toString() + "收到了消息：\t" + tm.getText());
    }

    // 如果是Map消息
    if (message instanceof MapMessage) {
      MapMessage mm = (MapMessage) message;
      System.out.println("ConsumerService从队列" + destination.toString() + "收到了消息：\t"
          + mm.getString("name"));
    }

    // 如果是Object消息
    if (message instanceof ObjectMessage) {
      ObjectMessage om = (ObjectMessage) message;
      Staff staff = (Staff) om.getObject();
      System.out.println("ConsumerService从队列" + destination.toString() + "收到了消息：\t" + staff);
    }

    // 如果是bytes消息
    if (message instanceof BytesMessage) {
      byte[] b = new byte[1024];
      int len = -1;
      BytesMessage bm = (BytesMessage) message;
      while ((len = bm.readBytes(b)) != -1) {
        System.out.println(new String(b, 0, len));
      }
    }

    // 如果是Stream消息
    if (message instanceof StreamMessage) {
      StreamMessage sm = (StreamMessage) message;
      System.out.println(sm.readString());
      System.out.println(sm.readInt());
    }

  }