java onmessage监听消息队列_侦听消息队列的Message Listener类

Spring AMQP 是基于 Spring 框架的AMQP消息解决方案，提供模板化的发送和接收消息的抽象层，提供基于消息驱动的 POJO的消息监听等，简化了我们对于RabbitMQ相关程序的开发。

Spring AMQP包含一些模块，如：spring-amqp, spring-rabbit and spring-erlang等，每个模块分别由独立的一些Jar包组成。

AbstractAdaptableMessageListener用于在spring容器接收到消息后用于处理消息的抽象基类，如果需要使用自己定义的pojoL类来实现处理消息时，必须要继承该类，并实现onMessage()方法，如下：

public class MessageReceive extends AbstractAdaptableMessageListener {

private static final Logger LOGGER = LoggerFactory.getLogger(MessageReceive.class);

@Override

public void onMessage(Message message, Channel channel) throws Exception {

LOGGER.info("receive message:{}", new String(message.getBody(), "UTF-8"));

}

}

实现了MessageListener, ChannelAwareMessageListener接口

MessageListener

@FunctionalInterface

public interface MessageListener {

void onMessage(Message message);

}

@FunctionalInterface注解表示该接口是一个功能类接口

ChannelAwareMessageListener

@FunctionalInterface

public interface ChannelAwareMessageListener {

/**

* Callback for processing a received Rabbit message.

*

Implementors are supposed to process the given Message,

* typically sending reply messages through the given Session.

* @param message the received AMQP message (never null)

* @param channel the underlying Rabbit Channel (never null)

* @throws Exception Any.

*/

void onMessage(Message message, Channel channel) throws Exception;

}

在AbstractAdaptableMessageListener中实现了MessageListener类的onMessage(Message message)方法，其实际实现的还是ChannelAwareMessageListener类中的onMessage方法，channel设置为null

@Override

public void onMessage(Message message) {

try {

onMessage(message, null);

}

catch (Exception e) {

throw new ListenerExecutionFailedException("Listener threw exception", e, message);

}

}

自定义消息处理的POJO类继承AbstractAdaptableMessageListener类后，重写onMessage方法，当spring容器接收消息后，会自动交由onMessage进行处理。