Java消息隊列RabbitMQ之消息模式詳解
消費(fèi)端限流
什么是消費(fèi)端的限流?
假設(shè)一個場景,首先,我們RabbitMQ服務(wù)器有上萬條未處理的消息,我們隨便打開一個消費(fèi)者客戶端,會出現(xiàn)下面情況: 巨量的消息瞬間全部推送過來,但是我們單個客戶端無法同時處理這么多數(shù)據(jù)!
消費(fèi)端限流RabbitMQ提供的解決方案
RabbitMQ提供了一種qos(服務(wù)質(zhì)量保證)功能,即在非自動確認(rèn)消息的前提下,如果一定數(shù)目的消息(通過基于Consmer或者Channel設(shè)置Qos的值)未被確認(rèn)前,不進(jìn)行消費(fèi)新的消息
Void BasicQos(uint prefetchSize, ushort prefetchCount, bool global);
prefetchSize:0 不限制消息大小
prefetchSize:會告訴RabbitMQ不要同時給一個消費(fèi)者推送多于N個消息,即一旦有N個消息還沒有ack,則該Consmer將block(阻塞)掉,直到有消息ack
Global:tre\false是否將上面設(shè)置應(yīng)用于Channel;簡單來說,就是上面限制是Channel級別的還是Consmer級
注意:
prefetchSize和global這兩項,RabbitMQ沒有實現(xiàn),暫且不研究;
prefetch_cont在no_ask=false的情況下生效,即在自動應(yīng)答的情況下,這兩個值是不生效的;
自定義消費(fèi)端代碼
package com.xieminglu.rabbitmqapi.limit; import com.rabbitmq.client.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.DefaultConsumer; import com.rabbitmq.client.Envelope; import java.io.IOException; 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); } }
消費(fèi)端代碼
package com.xieminglu.rabbitmqapi.limit; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; public class Consumer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); 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設(shè)置為 false channel.basicQos(0, 1, false); channel.basicConsume(queueName, false, new MyConsumer(channel)); } }
提供方代碼
package com.xieminglu.rabbitmqapi.limit; 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("192.168.248.134"); 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()); } } }
消息的ACK與重回隊列
消費(fèi)端手工ACK與NACK
消費(fèi)端進(jìn)行消費(fèi)的時候,如果由于業(yè)務(wù)異常我們可以進(jìn)行日志的記錄,然后進(jìn)行補(bǔ)償
如果由于服務(wù)器宕機(jī)等嚴(yán)重問題,那么我們就需要手工進(jìn)行ACK,保障消費(fèi)端消費(fèi)成功!
消費(fèi)端的重回隊列
消費(fèi)端重回隊列是為了對沒有處理成功的消息,把消息重新回遞給Broker!
一般我們在實際應(yīng)用中,都會關(guān)閉重回隊列,也就是設(shè)置為False;因為重回隊列消息有很大概率依然會處理失??!
自定義消費(fèi)者代碼
package com.xieminglu.rabbitmqapi.ack; import com.rabbitmq.client.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.DefaultConsumer; import com.rabbitmq.client.Envelope; import java.io.IOException; 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) { // 手動簽收,重回隊列 channel.basicNack(envelope.getDeliveryTag(), false, true); } else { channel.basicAck(envelope.getDeliveryTag(), false); } } }
消費(fèi)者代碼
package com.xieminglu.rabbitmqapi.ack; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; public class Consumer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); 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); // 手工簽收 必須要關(guān)閉 autoAck = false channel.basicConsume(queueName, false, new MyConsumer(channel)); } }
生產(chǎn)者代碼
package com.xieminglu.rabbitmqapi.ack; import com.rabbitmq.client.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import java.util.HashMap; import java.util.Map; public class Producer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); 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()); } } }
TTL消息
TTL是Time To Live的縮寫,也就是生存時間
- RabbitMQ支持消息的過期時間,在消息發(fā)送時可以進(jìn)行指定
- RabbitMQ支持隊列的過期時間,從消息入隊列開始計算,只要超過了隊列的超時時間配置,那么消息自動的清除
純控制臺操作(演示TTL隊列消息特點(diǎn)) 針對隊列,只要是這個隊列的消息,就只有這么長的存活時間
注意:主要針對消息設(shè)置,跟交換機(jī)、隊列、消費(fèi)者設(shè)置毫無關(guān)系
消費(fèi)端代碼
package com.xieminglu.rabbitmqapi.ttl; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.QueueingConsumer; import java.util.Map; public class Consumer { public static void main(String[] args) throws Exception { //1 創(chuàng)建一個ConnectionFactory, 并進(jìn)行配置 ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); //2 通過連接工廠創(chuàng)建連接 Connection connection = connectionFactory.newConnection(); //3 通過connection創(chuàng)建一個Channel Channel channel = connection.createChannel(); //4 聲明(創(chuàng)建)一個隊列 String queueName = "test001"; channel.queueDeclare(queueName, true, false, false, null); //5 創(chuàng)建消費(fèi)者 QueueingConsumer queueingConsumer = new QueueingConsumer(channel); //6 設(shè)置Channel channel.basicConsume(queueName, true, queueingConsumer); while(true){ //7 獲取消息 QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery(); String msg = new String(delivery.getBody()); System.err.println("消費(fèi)端: " + msg); Map<String, Object> headers = delivery.getProperties().getHeaders(); System.err.println("headers get my1 value: " + headers.get("my1")); //Envelope envelope = delivery.getEnvelope(); } } }
生產(chǎn)端代碼
package com.xieminglu.rabbitmqapi.ttl; import com.rabbitmq.client.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import java.util.HashMap; import java.util.Map; public class Procuder { public static void main(String[] args) throws Exception { //1 創(chuàng)建一個ConnectionFactory, 并進(jìn)行配置 ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); //2 通過連接工廠創(chuàng)建連接 Connection connection = connectionFactory.newConnection(); //3 通過connection創(chuàng)建一個Channel Channel channel = connection.createChannel(); Map<String, Object> headers = new HashMap<>(); headers.put("my1", "111"); headers.put("my2", "222"); AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder() .deliveryMode(2) .contentEncoding("UTF-8") .expiration("10000") .headers(headers) .build(); //4 通過Channel發(fā)送數(shù)據(jù) for(int i=0; i < 5; i++){ String msg = "Hello RabbitMQ!"; //1 exchange 2 routingKey channel.basicPublish("", "test001", properties, msg.getBytes()); } //5 記得要關(guān)閉相關(guān)的連接 channel.close(); connection.close(); } }
死信隊列
利用DLX,當(dāng)消息在一個隊列中變成死信(dead message)之后,它能被重新pblish到另一個Exchange,這個Exchange就是DLX
消息變成死信有以下幾種情況
- 消息被拒絕(basic.reject/basic.nack)并且reqee=false 消息TTL過期 隊列達(dá)到最大長度
- 死信隊列的特點(diǎn) DLX也是一個正常的Exchange,和一般的Exchange沒有區(qū)別,它能在任何的隊列上被指定,實際上就是設(shè)置某個隊列的屬性;
- 當(dāng)這個隊列中有死信時,RabbitMQ就會自動的將這個消息重新發(fā)布到設(shè)置的Exchange上去,進(jìn)而被路由到另一個隊列;
- 可以監(jiān)聽這個隊列中消息做相應(yīng)的處理,這個特性可以彌補(bǔ)RabbitMQ3.0以前支持的immediate參數(shù)的功能;
死信隊列設(shè)置
首先需要設(shè)置死信隊列的Exchange和Qee,然后進(jìn)行綁定:
- Exchange:dlx.exchange
- Qee:dlx.qee
- RotingKey:#
然后我們進(jìn)行正常聲明交換機(jī)、隊列、綁定,只不過我們需要在隊列加上一個參數(shù)即可:
Argments.pt(“x-dead-letter-exchange”,”dlx.exchange”);
這樣消息在過期、reqee、隊列在達(dá)到最大長度時,消息就可以直接路由到死信隊列!
自定義消費(fèi)端
package com.xieminglu.rabbitmqapi.dlx; import com.rabbitmq.client.AMQP; import com.rabbitmq.client.Channel; import com.rabbitmq.client.DefaultConsumer; import com.rabbitmq.client.Envelope; import java.io.IOException; public class MyConsumer extends DefaultConsumer { public MyConsumer(Channel channel) { super(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)); } }
消費(fèi)端代碼
package com.xieminglu.rabbitmqapi.dlx; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import java.util.HashMap; import java.util.Map; public class Consumer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.248.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); Connection connection = connectionFactory.newConnection(); Channel channel = connection.createChannel(); // 這就是一個普通的交換機(jī) 和 隊列 以及路由 String exchangeName = "test_dlx_exchange"; String routingKey = "dlx.#"; String queueName = "test_dlx_queue"; channel.exchangeDeclare(exchangeName, "topic", true, false, null); Map<String, Object> agruments = new HashMap<String, Object>(); agruments.put("x-dead-letter-exchange", "dlx.exchange"); //這個agruments屬性,要設(shè)置到聲明隊列上 channel.queueDeclare(queueName, true, false, false, agruments); channel.queueBind(queueName, exchangeName, routingKey); //要進(jìn)行死信隊列的聲明: channel.exchangeDeclare("dlx.exchange", "topic", true, false, null); channel.queueDeclare("dlx.queue", true, false, false, null); channel.queueBind("dlx.queue", "dlx.exchange", "#"); channel.basicConsume(queueName, true, new MyConsumer(channel)); } }
生產(chǎn)端代碼
package com.xieminglu.rabbitmqapi.dlx; 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("192.168.248.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); Connection connection = connectionFactory.newConnection(); Channel channel = connection.createChannel(); String exchange = "test_dlx_exchange"; String routingKey = "dlx.save"; String msg = "Hello RabbitMQ DLX Message"; for(int i =0; i<1; i ++){ AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder() .deliveryMode(2) .contentEncoding("UTF-8") .expiration("10000")//設(shè)置過期時間 .build(); channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes()); } } }
本節(jié)學(xué)習(xí)了RabbitMQ的高級特性,首先介紹了互聯(lián)網(wǎng)大廠在實際使用中是如何保障100%的消息投遞成功和冪等性的,以及對RabbitMQ的確認(rèn)消息、返回消息、ACK與重回隊列、消息的限流,以及對超時時間、死信隊列的使用
到此這篇關(guān)于Java消息隊列RabbitMQ之消息模式詳解的文章就介紹到這了,更多相關(guān)RabbitMQ之消息模式內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家!
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