rabbitMQ学习（六）

请求模式

客户端：

import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.AMQP.BasicProperties;
import java.util.UUID;

public class RPCClient {

  private Connection connection;
  private Channel channel;
  private String requestQueueName = "rpc_queue";
  private String replyQueueName;
  private QueueingConsumer consumer;

  public RPCClient() throws Exception {
    ConnectionFactory factory = new ConnectionFactory();
    factory.setHost("localhost");
    connection = factory.newConnection();
    channel = connection.createChannel();

    replyQueueName = channel.queueDeclare().getQueue();
    consumer = new QueueingConsumer(channel);
    channel.basicConsume(replyQueueName, true, consumer);
  }

  public String call(String message) throws Exception {
    String response = null;
    String corrId = UUID.randomUUID().toString();

    BasicProperties props = new BasicProperties
                                .Builder()
                                .correlationId(corrId)
                                .replyTo(replyQueueName)
                                .build();

    channel.basicPublish("", requestQueueName, props, message.getBytes("UTF-8"));

    while (true) {
      QueueingConsumer.Delivery delivery = consumer.nextDelivery();
      if (delivery.getProperties().getCorrelationId().equals(corrId)) {
        response = new String(delivery.getBody(),"UTF-8");
        break;
      }
    }

    return response;
  }

  public void close() throws Exception {
    connection.close();
  }

  public static void main(String[] argv) {
    RPCClient fibonacciRpc = null;
    String response = null;
    try {
      fibonacciRpc = new RPCClient();

      System.out.println(" [x] Requesting fib(30)");
      response = fibonacciRpc.call("30");
      System.out.println(" [.] Got '" + response + "'");
    }
    catch  (Exception e) {
      e.printStackTrace();
    }
    finally {
      if (fibonacciRpc!= null) {
        try {
          fibonacciRpc.close();
        }
        catch (Exception ignore) {}
      }
    }
  }
}

　　

服务端：

import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.AMQP.BasicProperties;

public class RPCServer {

  private static final String RPC_QUEUE_NAME = "rpc_queue";

  private static int fib(int n) {
    if (n ==0) return 0;
    if (n == 1) return 1;
    return fib(n-1) + fib(n-2);
  }

  public static void main(String[] argv) {
    Connection connection = null;
    Channel channel = null;
    try {
      ConnectionFactory factory = new ConnectionFactory();
      factory.setHost("localhost");

      connection = factory.newConnection();
      channel = connection.createChannel();

      channel.queueDeclare(RPC_QUEUE_NAME, false, false, false, null);

      channel.basicQos(1);

      QueueingConsumer consumer = new QueueingConsumer(channel);
      channel.basicConsume(RPC_QUEUE_NAME, false, consumer);

      System.out.println(" [x] Awaiting RPC requests");

      while (true) {
        String response = null;

        QueueingConsumer.Delivery delivery = consumer.nextDelivery();

        BasicProperties props = delivery.getProperties();
        BasicProperties replyProps = new BasicProperties
                                         .Builder()
                                         .correlationId(props.getCorrelationId())
                                         .build();

        try {
          String message = new String(delivery.getBody(),"UTF-8");
          int n = Integer.parseInt(message);

          System.out.println(" [.] fib(" + message + ")");
          response = "" + fib(n);
        }
        catch (Exception e){
          System.out.println(" [.] " + e.toString());
          response = "";
        }
        finally {
          channel.basicPublish( "", props.getReplyTo(), replyProps, response.getBytes("UTF-8"));

          channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }
      }
    }
    catch  (Exception e) {
      e.printStackTrace();
    }
    finally {
      if (connection != null) {
        try {
          connection.close();
        }
        catch (Exception ignore) {}
      }
    }
  }
}

　　

参考资料

http://www.rabbitmq.com/tutorials/tutorial-six-java.html