rabbitmq学习笔记

前一阵子写SEDA异步框架的时候，使用了rabbitmq作为分布式消息队列（见前文），把一些学习官网教程的笔记简单备忘。示例都来自官网

 

Part 2 Work Queues

 

1、round-robin dispatchering  

缺陷：存在不能准确负载均衡的弊端

2、fair dispatch  --> 针对管道

采用channel.basicQos(prefetchCount); 缺陷：可能带来队列塞

3、message acknowledge  --> 针对消费者

boolean autoAck = false;channel.basicConsume("hello", autoAck, consumer);//默认是true，别用反了

while (true) {
  QueueingConsumer.Delivery delivery = consumer.nextDelivery();
  //...     
  channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);// 记得手动加上发送ack。不然server会认为client没收到
}

4、Message durability  --> 针对队列

采用boolean durable = true;channel.queueDeclare("hello", durable, false, false, null);

5、persistent --> 针对发布者

import com.rabbitmq.client.MessageProperties;

channel.basicPublish("", "task_queue", MessageProperties.PERSISTENT_TEXT_PLAIN,message.getBytes());

 

 

example:

 

 

public class NewTask {

private static final String TASK_QUEUE_NAME = "task_queue";

public static void main(String[] argv)
                      throws java.io.IOException {

    ConnectionFactory factory = new ConnectionFactory();
    factory.setHost("localhost");
    Connection connection = factory.newConnection();
    Channel channel = connection.createChannel();

    channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);

    String message = getMessage(argv);

    channel.basicPublish( "", TASK_QUEUE_NAME,
            MessageProperties.PERSISTENT_TEXT_PLAIN,
            message.getBytes());
    System.out.println(" [x] Sent '" + message + "'");

    channel.close();
    connection.close();
  }     
  //...
}

 

public class Worker {

private static final String TASK_QUEUE_NAME = "task_queue";

public static void main(String[] argv)
                      throws java.io.IOException,
                      java.lang.InterruptedException {

    ConnectionFactory factory = new ConnectionFactory();
    factory.setHost("localhost");
    Connection connection = factory.newConnection();
    Channel channel = connection.createChannel();

    channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);
    System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

    channel.basicQos(1);

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

    while (true) {
          QueueingConsumer.Delivery delivery = consumer.nextDelivery();
          String message = new String(delivery.getBody());

          System.out.println(" [x] Received '" + message + "'");  
          doWork(message);
          System.out.println(" [x] Done" );

          channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
    }
  }
  //...
}

 

Part 3 Publish/Subscribe

 

1、Exchanges(类似block)

type：direct, topic, headers, fanout(类似广播)

Declared way:  channel.exchangeDeclare("logs", "fanout");

 

2、Temporary queue

Non-durable, exclusive, autodelete

String queueName = channel.queueDeclare().getQueue();

 

3、Bindings

channel.queueBind(queueName, "logs", "");

 

example:

 

 

public class EmitLog {
private static final String EXCHANGE_NAME = "logs";
public static void main(String[] argv)
                  throws java.io.IOException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String message = getMessage(argv);
        channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes());
        System.out.println(" [x] Sent '" + message + "'");
        channel.close();
        connection.close();
    }
    //...
}
 
 
 
public class ReceiveLogs {
private static final String EXCHANGE_NAME = "logs";
public static void main(String[] argv)
                  throws java.io.IOException,
                  java.lang.InterruptedException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = channel.queueDeclare().getQueue();
        channel.queueBind(queueName, EXCHANGE_NAME, "");
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(queueName, true, consumer);
        while (true) {
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println(" [x] Received '" + message + "'");
        }
    }
}

 

 

Part 4 Routing

1、Direct exchange

type：direct, topic, headers, fanout(类似广播)

Declared way:  channel.exchangeDeclare("logs", "fanout");

 

2、Multiple bindings

 

example:

 

 

public class EmitLogDirect {
private static final String EXCHANGE_NAME = "direct_logs";
public static void main(String[] argv)
                  throws java.io.IOException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        String severity = getSeverity(argv);
        String message = getMessage(argv);
        channel.basicPublish(EXCHANGE_NAME, severity, null,    message.getBytes());
        System.out.println(" [x] Sent '" + severity + "':'" + message + "'");
        channel.close();
        connection.close();
    }
    //..
}
 
 
 
public class ReceiveLogsDirect {
private static final String EXCHANGE_NAME = "direct_logs";
public static void main(String[] argv)
                  throws java.io.IOException,
                  java.lang.InterruptedException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        String queueName = channel.queueDeclare().getQueue();
        if (argv.length < 1){
            System.err.println("Usage: ReceiveLogsDirect [info] [warning] [error]");
            System.exit(1);
        }
        for(String severity : argv){
            channel.queueBind(queueName, EXCHANGE_NAME, severity);
        }
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(queueName, true, consumer);
        while (true) {
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            String routingKey = delivery.getEnvelope().getRoutingKey();
            System.out.println(" [x] Received '" + routingKey + "':'" + message + "'");
        }
    }
}

 

 

Part 5 Topic

1、Topic exchange

比direct exchange方式好的地方是有通配符的概念在里面

* (star) can substitute for exactly one word.

# (hash) can substitute for zero or more words.

 

Delimited by dots

 

Routing_key up to the limit of 255 bytes

 

example:

 

public class EmitLogTopic {
private static final String EXCHANGE_NAME = "topic_logs";
public static void main(String[] argv)
                  throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        String routingKey = getRouting(argv);
        String message = getMessage(argv);
        channel.basicPublish(EXCHANGE_NAME, routingKey, null, message.getBytes());
        System.out.println(" [x] Sent '" + routingKey + "':'" + message + "'");
        connection.close();
    }
    //...
}
 
public class ReceiveLogsTopic {
private static final String EXCHANGE_NAME = "topic_logs";
public static void main(String[] argv)
                  throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        String queueName = channel.queueDeclare().getQueue();
        if (argv.length < 1){
            System.err.println("Usage: ReceiveLogsTopic [binding_key]...");
            System.exit(1);
        }
       for(String bindingKey : argv){
            channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);
        }
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(queueName, true, consumer);
        while (true) {
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            String routingKey = delivery.getEnvelope().getRoutingKey();
            System.out.println(" [x] Received '" + routingKey + "':'" + message + "'");
        }
    }
}
 

 

集群方案：

一般采用镜像队列，内存节点作为主服务器+磁盘节点做冗余。