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rabbitmq学习(四):利用rabbitmq实现远程rpc调用

  • 腾博游戏平台
  • 2019-05-22
  • 426人已阅读
简介一、rabbitmq实现rpc调用的原理·rabbitmq实现rpc的原理是:客户端向一个队列中发送消息,并注册一个回调的队列用于接收服务端返回的消息,该消息需要声明一个叫做corre

一、rabbitmq实现rpc调用的原理

·rabbitmq实现rpc的原理是:客户端向一个队列中发送消息,并注册一个回调的队列用于接收服务端返回的消息,该消息需要声明一个叫做correaltionId的属性,该属性将是该次请求的唯一标识。服务端在接受到消息(在需要时可以验证correaltionId)后,处理消息,并将消息发送到客户端注册的回调队列中。原理图如下:  

  

二、代码实现

  下面我们将模拟实现一个rpc客户端和rpc服务端。客户端给服务端发送message,服务端收到后处理message,再将处理后的消息返给客户端

  rpc客户端

  

/** * rpc客户端 */public class RpcClient { //发送消息的队列名称 private static final String RPC_QUEUE_NAME = "rpc_queue"; public static void main(String[] args) { ConnectionFactory connectionFactory = new ConnectionFactory(); Connection connection = null; Channel channel = null; try { connection = connectionFactory.newConnection(); channel = connection.createChannel(); //创建回调队列 String callbackQueue = channel.queueDeclare().getQueue(); //创建回调队列,消费者从回调队列中接收服务端传送的消息 QueueingConsumer consumer = new QueueingConsumer(channel); channel.basicConsume(callbackQueue,true,consumer); //创建消息带有correlationId的消息属性 String correlationId = UUID.randomUUID().toString(); AMQP.BasicProperties basicProperties = new AMQP.BasicProperties().builder().correlationId(correlationId).replyTo(callbackQueue).build(); String message = "hello rabbitmq"; channel.basicPublish("",RPC_QUEUE_NAME,basicProperties,message.getBytes()); System.out.println("RpcClient send message " + message + ", correaltionId = " + correlationId); //接收回调消息 while (true){ QueueingConsumer.Delivery delivery = consumer.nextDelivery(); String receivedCorrelationId = delivery.getProperties().getCorrelationId(); if(correlationId.equals(receivedCorrelationId)){ System.out.println("RpcClient receive format message " + new String(delivery.getBody(), "UTF-8") + ", correaltionId = " + correlationId); break; } } } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } finally { try { channel.close(); connection.close(); } catch (IOException e) { e.printStackTrace(); } } }}

 

   rpc服务端

  

/** * rpc服务器 */public class RpcServer { private static final String RPC_QUEUE_NAME = "rpc_queue"; private static String format(String message){ return "......" + message + "......"; } public static void main(String[] args) { ConnectionFactory connectionFactory = new ConnectionFactory(); Connection connection = null; try { connection = connectionFactory.newConnection(); Channel channel = connection.createChannel(); channel.queueDeclare(RPC_QUEUE_NAME,false,false,false,null); QueueingConsumer consumer = new QueueingConsumer(channel); //声明消费者预取的消息数量 channel.basicQos(1); channel.basicConsume(RPC_QUEUE_NAME,false,consumer);//采用手动回复消息 System.out.println("RpcServer waitting for receive message"); while (true){ //接收并处理消息 QueueingConsumer.Delivery delivery = consumer.nextDelivery(); String message = new String(delivery.getBody(), "UTF-8"); System.out.println("RpcServer receive message " + message); String response = format(message); //确认收到消息 channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false); //取出消息的correlationId AMQP.BasicProperties properties = delivery.getProperties(); String correlationId = properties.getCorrelationId(); //创建具有与接收消息相同的correlationId的消息属性 AMQP.BasicProperties replyProperties = new AMQP.BasicProperties().builder().correlationId(correlationId).build(); channel.basicPublish("",properties.getReplyTo(),replyProperties,response.getBytes()); } } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } }}

   先运行服务端,再运行客户端,结果如下:

  RpcClient

  

  RpcServer

  

  

 

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