300字范文 > RabbitMQ-交换机（Fanout Direct Topics ）血战

RabbitMQ-交换机（Fanout Direct Topics ）血战

时间：2022-05-09 07:42:40

Exchanges

编辑

临时队列

绑定 bindings

交换机的三种交换方式

Fanout exchange

编辑

Direct exchange

Topics exchange

RabbitMQ附加面试题：

Exchanges

RabbitMQ消息传递的核心思想是：生产者生产的消息不会直接发送到队列中！！！！

相反：生产者只能将消息发送到交换机（exchanges）

交换机一方面接受生产者信息，一方面将它们推入队列中

Exchanges 的类型：

直连(direct), 主题(topic) , 标题(headers) , 扇出(fanout)

无名exchange：

在前面部分我们对 exchange 一无所知，但仍然能够将消息发送到队列。之前能实现的原因是因为我们使用的是默认交换，我们通过空字符串(“”)进行标识。

第一个参数是交换机名称。空字符串表示默认无名交换机：消息能路由发送到队列中其实是由 routingKey(bindingkey)绑定 key 指定的，如果它存在的话

临时队列

一旦我们断开了消费者的连接，临时队列将被自动删除。

创建临时队列的方式如下:

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

绑定 bindings

什么是 bingding 呢，binding 其实是 exchange 和 queue 之间的桥梁，它告诉我们 exchange 和那个队列进行了绑定关系。比如说下面这张图告诉我们的就是 X 与 Q1 和 Q2 进行了绑定

交换机的三种交换方式

Fanout:分裂交换机扇出交换机

Direct：直连交换机路由键（一对一）

Topics：主题路由键更加复杂，更加适用于多套场景

Fanout exchange

Fanout 介绍

它是将接收到的所有消息广播到它知道的所有队列中。系统中默认有些 exchange 类型

Fanout 实战

说明这种模式，我们将构建一个简单的日志系统，它将由两个程序组成:第一个程序将发出日志消息，第二个程序是消费者。其中我们会启动两个消费者，其中一个消费者接收到消息后把日志存储在磁盘，

ReceiveLogs01 将接收到的消息打印在控制台

/*** Fanout*/public class ReceiveLogs01 {private static final String EXCHANGE_NAME = "logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel(); //定义交换机channel.exchangeDeclare(EXCHANGE_NAME, "fanout");/*** 生成一个临时的队列队列的名称是随机的* 当消费者断开和该队列的连接时队列自动删除*/String queueName = channel.queueDeclare().getQueue();//把该临时队列绑定我们的 exchange 其中 routingkey(也称之为 binding key)为空字符串//用一个队列跟我们交换机绑定channel.queueBind(queueName, EXCHANGE_NAME, "");System.out.println("等待接收消息,把接收到的消息打印在屏幕........... ");//发送回调DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("控制台打印接收到的消息" + message);};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

eceiveLogs02 把消息写出到文件

/*** Fanout*/public class ReceiveLogs02 {private static final String EXCHANGE_NAME = "logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, "fanout"); /*** 生成一个临时的队列队列的名称是随机的* 当消费者断开和该队列的连接时队列自动删除*/String queueName = channel.queueDeclare().getQueue();//把该临时队列绑定我们的 exchange 其中 routingkey(也称之为 binding key)为空字符串channel.queueBind(queueName, EXCHANGE_NAME, "");System.out.println("等待接收消息,把接收到的消息写到文件........... ");//发送回调DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");File file = new File("D:\\test\\rabbitmq_info.txt");FileUtils.writeStringToFile(file,message,"UTF-8");System.out.println("数据写入文件成功");};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

EmitLog(生产者) 发送消息给两个消费者接收：

public class EmitLog {private static final String EXCHANGE_NAME = "logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();/*** 声明一个 exchange 交换机* 1.exchange 的名称* 2.exchange 的类型* fanout 分裂交换机*/channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);Scanner sc = new Scanner(System.in);System.out.println("请输入信息");while (sc.hasNext()) {String message = sc.nextLine();channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));System.out.println("生产者发出消息" + message);}}}

Fanout：分裂模式也称扇出模式

一个消息默认的情况下只能被一个消费者消费，但存在交换机下，一个消息可以被多个消费者消费

Direct exchange

超级简单看图

Direct: 直连交换机

根据条件进行消费

ReceiveLogsDirect01（消费者）

/*** Direct*/public class ReceiveLogsDirect01 {private static final String EXCHANGE_NAME = "direct_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);String queueName = "disk";//队列声明channel.queueDeclare(queueName, false, false, false, null); //队列绑定//只能接收error的消息channel.queueBind(queueName, EXCHANGE_NAME, "error");System.out.println("等待接收消息...");//发送回调DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");message = "接收绑定键:" + delivery.getEnvelope().getRoutingKey() + ",消息:" + message;System.out.println("error 消息已经接收：\n" + message);};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

ReceiveLogsDirect02 （消费者2）

* Direct*/public class ReceiveLogsDirect02 {private static final String EXCHANGE_NAME = "direct_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);String queueName = "console"; //队列声明channel.queueDeclare(queueName, false, false, false, null);//队列绑定//只能接受info warning 消息channel.queueBind(queueName, EXCHANGE_NAME, "info");channel.queueBind(queueName, EXCHANGE_NAME, "warning");System.out.println("等待接收消息...");//发送回调DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");message = "接收绑定键:" + delivery.getEnvelope().getRoutingKey() + ",消息:" + message;System.out.println("info和warning 消息已经接收：\n" + message);};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

EmitLogDirect （生产者）

/*** Direct 直连交换机*/public class EmitLogDirect {private static final String EXCHANGE_NAME = "direct_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel(); //定义交换机 Directchannel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);//创建多个 bindingKeyMap<String, String> bindingKeyMap = new HashMap<>();bindingKeyMap.put("info", "普通 info 信息");bindingKeyMap.put("warning", "警告 warning 信息");bindingKeyMap.put("error", "错误 error 信息");//debug 没有消费这接收这个消息所有就丢失了bindingKeyMap.put("debug", "调试 debug 信息");for (Map.Entry<String, String> bindingKeyEntry : bindingKeyMap.entrySet()) {//获取 key valueString bindingKey = bindingKeyEntry.getKey();String message = bindingKeyEntry.getValue(); /*** 发布消息* 1.交换机* 2.路由键* 3.参数* 4.消息主体*/channel.basicPublish(EXCHANGE_NAME, bindingKey, null, message.getBytes("UTF-8"));System.out.println("生产者发出消息:" + message);}}}

Topics exchange

Topics : (实用性最强) *：代表一个 #:代表多个对比上两个多了个通配符

Q1-->绑定的是中间带 orange 带 3 个单词的字符串 (*.orange.*)Q2-->绑定的是最后一个单词是 rabbit 的 3 个单词 (*.*.rabbit)第一个单词是 lazy 的多个单词 (lazy.#)

数据接收情况：

注意：

当一个队列绑定键是#，那么这个队列将接收所有数据，就有点像 fanout 了如果队列绑定键当中没有#和*出现，那么该队列绑定类型就是 direct 了

Topic实战

ReceiveLogsTopic01 （消费者）

public class ReceiveLogsTopic01 {private static final String EXCHANGE_NAME = "topic_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.TOPIC); //声明 Q1 队列与绑定关系String queueName = "Q1"; //声明channel.queueDeclare(queueName, false, false, false, null);//绑定channel.queueBind(queueName, EXCHANGE_NAME, "*.orange.*");System.out.println("等待接收消息........... ");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println(" 接收队列:" + queueName + " 绑定键:" + delivery.getEnvelope().getRoutingKey() + ",消息:" + message);};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

ReceiveLogsTopic02(消费者)

public class ReceiveLogsTopic02 {private static final String EXCHANGE_NAME = "topic_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.TOPIC); //声明 Q2 队列与绑定关系String queueName = "Q2"; //声明channel.queueDeclare(queueName, false, false, false, null); //绑定channel.queueBind(queueName, EXCHANGE_NAME, "*.*.rabbit");channel.queueBind(queueName, EXCHANGE_NAME, "lazy.#");System.out.println("等待接收消息........... ");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println(" 接收队列:" + queueName + " 绑定键:" + delivery.getEnvelope().getRoutingKey() + ",消息:" + message);};channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});}}

EmitLogTopic （生产者）

/*** 发送端*/public class EmitLogTopic {private static final String EXCHANGE_NAME = "topic_logs";public static void main(String[] args) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.TOPIC); /*** Q1-->绑定的是*中间带 orange 带 3 个单词的字符串(*.orange.*)* Q2-->绑定的是*最后一个单词是 rabbit 的 3 个单词(*.*.rabbit)*第一个单词是 lazy 的多个单词(lazy.#)**/Map<String, String> bindingKeyMap = new HashMap<>();bindingKeyMap.put("quick.orange.rabbit", "被队列 Q1Q2 接收到");bindingKeyMap.put("lazy.orange.elephant", "被队列 Q1Q2 接收到");bindingKeyMap.put("quick.orange.fox", "被队列 Q1 接收到");bindingKeyMap.put("laz.brown.fox", "被队列 Q2 接收到");bindingKeyMap.put("lazy.pink.rabbit", "虽然满足两个绑定但只被队列 Q2 接收一次");bindingKeyMap.put("quick.brown.fox", "不匹配任何绑定不会被任何队列接收到会被丢弃");bindingKeyMap.put("quick.orange.male.rabbit", "是四个单词不匹配任何绑定会被丢弃");bindingKeyMap.put("lazy.orange.male.rabbit", "是四个单词但匹配 Q2");for (Map.Entry<String, String> bindingKeyEntry : bindingKeyMap.entrySet()) {String bindingKey = bindingKeyEntry.getKey();String message = bindingKeyEntry.getValue();channel.basicPublish(EXCHANGE_NAME, bindingKey, null, message.getBytes("UTF-8"));System.out.println("生产者发出消息：" + message);}}}