RabbitMQ--Return消息机制、消费端限流操作、消费端ACK(四)

于 2019-02-18 16:43:28 发布
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分类专栏： RabbitMQ 文章标签： RabbitMQ Return消息机制 消费端限流操作 消费端ACK
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本文链接：https://blog.youkuaiyun.com/EndTheme_Xin/article/details/87625237
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目录

 

目录

Confirm消息机制

什么是confirm消息机制

Return 消息机制

什么是Return消息机制？

示例代码

Producer.java

Consumer.java

消费端限流

什么是消费端限流？

消费端限流的配置

示例代码：

Consumer.java

MyConsumer.java

Producer.java

消费端ACK与重回队列

消费端ACK使用场景

重回队列使用场景

示例代码：

Consumer.java

Myconsumer.java

Producer.java

Confirm消息机制

什么是confirm消息机制

消息的确认是指生产者投递消息后，如果Broker接收到消息，则会给生产者一个应答。生产者进行接收应答，用来确认这条消息是否正常的发送到Broker，这种方式也是消息可靠性投递的核心保障。

 

示例代码:

Producer.java

import java.io.IOException;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.ConfirmListener;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		
		//1 创建ConnectionFactory
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		//2 获取C	onnection
		Connection connection = connectionFactory.newConnection();
		
		//3 通过Connection创建一个新的Channel
		Channel channel = connection.createChannel();
		
		
		//4 指定我们的消息投递模式: 消息的确认模式 
		channel.confirmSelect();
		
		String exchangeName = "test_confirm_exchange";
		String routingKey = "confirm.save";
		
		//5 发送一条消息
		String msg = "Hello RabbitMQ Send confirm message!";
		channel.basicPublish(exchangeName, routingKey, null, msg.getBytes());
		
		//6 添加一个确认监听
		channel.addConfirmListener(new ConfirmListener() {
			@Override
			public void handleNack(long deliveryTag, boolean multiple) throws IOException {
				System.err.println("-------no ack!-----------");
			}
			
			@Override
			public void handleAck(long deliveryTag, boolean multiple) throws IOException {
				System.err.println("-------ack!-----------");
			}
		});
		
	}
}

Consumer.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.QueueingConsumer.Delivery;

public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		//1 创建ConnectionFactory
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		//2 获取Connection
		Connection connection = connectionFactory.newConnection();
		
		//3 通过Connection创建一个新的Channel
		Channel channel = connection.createChannel();
		
		String exchangeName = "test_confirm_exchange";
		String routingKey = "confirm.#";
		String queueName = "test_confirm_queue";
		
		//4 声明交换机和队列 然后进行绑定设置, 最后制定路由Key
		channel.exchangeDeclare(exchangeName, "topic", true);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		//5 创建消费者 
		QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
		channel.basicConsume(queueName, true, queueingConsumer);
		
		while(true){
			Delivery delivery = queueingConsumer.nextDelivery();
			String msg = new String(delivery.getBody());
			
			System.err.println("消费端: " + msg);
		}
		
		
	}
}

 

Return 消息机制

什么是Return消息机制？

Return Listener 可以用于处理一些不可路由的消息！

消息的生产者总是绑定一个Exchange和RoutingKey，把消息发送到某个队列去，然后通过消费者监听消费处理！

但是某些情况下它可能找不到对应的RoutingKey或者发送了一个不可达的消息，这时候需要Return机制来处理。

在基础API中有一个关键的配置项：Mandatory，如果设置为True，则使用的监听器会获取到该条不可到达的消息，然后进行业务处理，如果设置为False，那么MQ会删除这条消息。

 

示例代码

Producer.java

import java.io.IOException;

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

public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_return_exchange";
		String routingKey = "return.save";
		String routingKeyError = "abc.save";
		
		String msg = "Hello RabbitMQ Return Message";
		
		
		channel.addReturnListener(new ReturnListener() {
			@Override
			public void handleReturn(int replyCode, String replyText, String exchange,
					String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {
				// 你的业务代码
				System.err.println("---------handle  return----------");
				System.err.println("replyCode: " + replyCode);
				System.err.println("replyText: " + replyText);
				System.err.println("exchange: " + exchange);
				System.err.println("routingKey: " + routingKey);
				System.err.println("properties: " + properties);
				System.err.println("body: " + new String(body));
			}
		});
		
		
		channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());
	}
}

Consumer.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.QueueingConsumer.Delivery;

public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchangeName = "test_return_exchange";
		String routingKey = "return.#";
		String queueName = "test_return_queue";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
		
		channel.basicConsume(queueName, true, queueingConsumer);
		
		while(true){
			Delivery delivery = queueingConsumer.nextDelivery();
			String msg = new String(delivery.getBody());
			System.err.println("消费者: " + msg);
		}
	}
}

 

消费端限流

什么是消费端限流？

RabbitMQ提供了一种qos功能（服务质量保证），即是在非自动确认消息（手动ACK）的前提下，如果一定数目（通过comsume或者channel设置Qos的值）的消息没有被消费前，不进行新的消息消费。

消费端限流的配置

prefetchSize:0

prefetchCount: 最大推送N个消息给消费者，（前N个都没有ACK）直到有消息被消费前，推送的新消息都会被block

global:true\false      true限制级别为channel，false限制级别为consumer

 

PS.当no_ack=false（即开启自动应答消息）时，限流配置将不生效。

示例代码：

Consumer.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.QueueingConsumer.Delivery;

public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		
		String exchangeName = "test_qos_exchange";
		String queueName = "test_qos_queue";
		String routingKey = "qos.#";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		//1 限流方式  第一件事就是 autoAck设置为 false
		
		channel.basicQos(0, 1, false);
		
		channel.basicConsume(queueName, false, new MyConsumer(channel));
		
		
	}
}

MyConsumer.java

import java.io.IOException;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class MyConsumer extends DefaultConsumer {


	private Channel channel ;
	
	public MyConsumer(Channel channel) {
		super(channel);
		this.channel = channel;
	}

	@Override
	public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
		System.err.println("-----------consume message----------");
		System.err.println("consumerTag: " + consumerTag);
		System.err.println("envelope: " + envelope);
		System.err.println("properties: " + properties);
		System.err.println("body: " + new String(body));
		
		channel.basicAck(envelope.getDeliveryTag(), false);
		
	}


}

Producer.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_qos_exchange";
		String routingKey = "qos.save";
		
		String msg = "Hello RabbitMQ QOS Message";
		
		for(int i =0; i<5; i ++){
			channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());
		}
		
	}
}

消费端ACK与重回队列

消费端ACK使用场景

1.消费端进行消费的时候，如果由于业务异常，可以通过日志记录，然后进行补偿！

2.如果由于服务器宕机等问题，则需要我们手动进行ACK保障消费端能成功消费！

重回队列使用场景

1.对没有处理成功的消息，重新投递回RabbitMQ

2.实际使用中，一般会关闭重回队列机制，设置为False

 

示例代码：

Consumer.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.QueueingConsumer.Delivery;

public class Consumer {

	
	public static void main(String[] args) throws Exception {
		
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchangeName = "test_ack_exchange";
		String queueName = "test_ack_queue";
		String routingKey = "ack.#";
		
		channel.exchangeDeclare(exchangeName, "topic", true, false, null);
		channel.queueDeclare(queueName, true, false, false, null);
		channel.queueBind(queueName, exchangeName, routingKey);
		
		// 手工签收 必须要关闭 autoAck = false
		channel.basicConsume(queueName, false, new MyConsumer(channel));
	}
}

Myconsumer.java

import java.io.IOException;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class MyConsumer extends DefaultConsumer {


	private Channel channel ;
	
	public MyConsumer(Channel channel) {
		super(channel);
		this.channel = channel;
	}

	@Override
	public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
		System.err.println("-----------consume message----------");
		System.err.println("body: " + new String(body));
		try {
			Thread.sleep(2000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		if((Integer)properties.getHeaders().get("num") == 0) {
			channel.basicNack(envelope.getDeliveryTag(), false, true);
		} else {
			channel.basicAck(envelope.getDeliveryTag(), false);
		}
		
	}


}

Producer.java

import java.util.HashMap;
import java.util.Map;

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

public class Producer {

	
	public static void main(String[] args) throws Exception {
		
		ConnectionFactory connectionFactory = new ConnectionFactory();
		connectionFactory.setHost("192.168.11.76");
		connectionFactory.setPort(5672);
		connectionFactory.setVirtualHost("/");
		
		Connection connection = connectionFactory.newConnection();
		Channel channel = connection.createChannel();
		
		String exchange = "test_ack_exchange";
		String routingKey = "ack.save";
		
		
		
		for(int i =0; i<5; i ++){
			
			Map<String, Object> headers = new HashMap<String, Object>();
			headers.put("num", i);
			
			AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
					.deliveryMode(2)
					.contentEncoding("UTF-8")
					.headers(headers)
					.build();
			String msg = "Hello RabbitMQ ACK Message " + i;
			channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
		}
		
	}
}

 

 

 

 

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