RabbitMQ 中的 7 种队列模式，写得太好了！
七种模式介绍与应用场景
简单模式（Hello World）
做最简单的事情，一个生产者对应一个消费者，RabbitMQ相当于一个消息代理，负责将A的消息转发给B
应用场景： 将发送的电子邮件放到消息队列，然后邮件服务在队列中获取邮件并发送给收件人
工作队列模式（Work queues）
在多个消费者之间分配任务（竞争的消费者模式），一个生产者对应多个消费者，一般适用于执行资源密集型任务，单个消费者处理不过来，需要多个消费者进行处理
应用场景： 一个订单的处理需要10s，有多个订单可以同时放到消息队列，然后让多个消费者同时处理，这样就是并行了，而不是单个消费者的串行情况
订阅模式（Publish/Subscribe）
一次向许多消费者发送消息，一个生产者发送的消息会被多个消费者获取，也就是将消息将广播到所有的消费者中。
应用场景： 更新商品库存后需要通知多个缓存和多个数据库，这里的结构应该是：
一个fanout类型交换机扇出两个个消息队列，分别为缓存消息队列、数据库消息队列 一个缓存消息队列对应着多个缓存消费者 一个数据库消息队列对应着多个数据库消费者
路由模式（Routing）
有选择地（Routing key）接收消息，发送消息到交换机并且要指定路由key ，消费者将队列绑定到交换机时需要指定路由key，仅消费指定路由key的消息
应用场景： 如在商品库存中增加了1台iphone12，iphone12促销活动消费者指定routing key为iphone12，只有此促销活动会接收到消息，其它促销活动不关心也不会消费此routing key的消息
主题模式（Topics）
根据主题（Topics）来接收消息，将路由key和某模式进行匹配，此时队列需要绑定在一个模式上，#匹配一个词或多个词，*只匹配一个词。
应用场景： 同上，iphone促销活动可以接收主题为iphone的消息，如iphone12、iphone13等
远程过程调用（RPC）
如果我们需要在远程计算机上运行功能并等待结果就可以使用RPC，具体流程可以看图。应用场景：需要等待接口返回数据，如订单支付
发布者确认（Publisher Confirms）
与发布者进行可靠的发布确认，发布者确认是RabbitMQ扩展，可以实现可靠的发布。在通道上启用发布者确认后，RabbitMQ将异步确认发送者发布的消息，这意味着它们已在服务器端处理。
应用场景： 对于消息可靠性要求较高，比如钱包扣款
代码演示
简单模式
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Sender {
private final static String QUEUE_NAME = "simple_queue";
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
// 声明队列
// queue：队列名
// durable：是否持久化
// exclusive：是否排外 即只允许该channel访问该队列 一般等于true的话用于一个队列只能有一个消费者来消费的场景
// autoDelete：是否自动删除 消费完删除
// arguments：其他属性
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
//消息内容
String message = "simplest mode message";
channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
System.out.println("[x]Sent '" + message + "'");
//最后关闭通关和连接
channel.close();
connection.close();
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Receiver {
private final static String QUEUE_NAME = "simplest_queue";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
// 获取连接
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
工作队列模式
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Receiver1 {
private final static String QUEUE_NAME = "queue_work";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 同一时刻服务器只会发送一条消息给消费者
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Receiver2 {
private final static String QUEUE_NAME = "queue_work";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 同一时刻服务器只会发送一条消息给消费者
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Sender {
private final static String QUEUE_NAME = "queue_work";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
// 声明队列
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
for (int i = 0; i < 100; i++) {
String message = "work mode message" + i;
channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
System.out.println("[x] Sent '" + message + "'");
Thread.sleep(i * 10);
}
channel.close();
connection.close();
}
}
发布订阅模式
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
public class Receive1 {
private static final String EXCHANGE_NAME = "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, "fanout");
String queueName = channel.queueDeclare().getQueue();
channel.queueBind(queueName, EXCHANGE_NAME, "");
System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
// 订阅消息的回调函数
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" + message + "'");
};
// 消费者，有消息时出发订阅回调函数
channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
public class Receive2 {
private static final String EXCHANGE_NAME = "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, "fanout");
String queueName = channel.queueDeclare().getQueue();
channel.queueBind(queueName, EXCHANGE_NAME, "");
System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
// 订阅消息的回调函数
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received2 '" + message + "'");
};
// 消费者，有消息时出发订阅回调函数
channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class Sender {
private static final String EXCHANGE_NAME = "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, "fanout");
String message = "publish subscribe message";
channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));
System.out.println(" [x] Sent '" + message + "'");
channel.close();
connection.close();
}
}
路由模式
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Receiver1 {
private final static String QUEUE_NAME = "queue_routing";
private final static String EXCHANGE_NAME = "exchange_direct";
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 指定路由的key，接收key和key2
channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key");
channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key2");
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DeliverCallback;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Receiver2 {
private final static String QUEUE_NAME = "queue_routing2";
private final static String EXCHANGE_NAME = "exchange_direct";
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 仅接收key2
channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key2");
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Sender {
private final static String EXCHANGE_NAME = "exchange_direct";
private final static String EXCHANGE_TYPE = "direct";
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
// 交换机声明
channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE);
// 只有routingKey相同的才会消费
String message = "routing mode message";
channel.basicPublish(EXCHANGE_NAME, "key2", null, message.getBytes());
System.out.println("[x] Sent '" + message + "'");
// channel.basicPublish(EXCHANGE_NAME, "key", null, message.getBytes());
// System.out.println("[x] Sent '" + message + "'");
channel.close();
connection.close();
}
}
主题模式
public class Receiver1 {
private final static String QUEUE_NAME = "queue_topic";
private final static String EXCHANGE_NAME = "exchange_topic";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 可以接收key.1
channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key.*");
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
public class Receiver1 {
private final static String QUEUE_NAME = "queue_topic";
private final static String EXCHANGE_NAME = "exchange_topic";
public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.queueDeclare(QUEUE_NAME, false, false, false, null);
// 可以接收key.1
channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key.*");
channel.basicQos(1);
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
String message = new String(delivery.getBody(), "UTF-8");
System.out.println(" [x] Received '" +
delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
};
channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
});
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.io.IOException;
import java.util.concurrent.TimeoutException;
public class Sender {
private final static String EXCHANGE_NAME = "exchange_topic";
private final static String EXCHANGE_TYPE = "topic";
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("localhost");
factory.setPort(5672);
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE);
String message = "topics model message with key.1";
channel.basicPublish(EXCHANGE_NAME, "key.1", null, message.getBytes());
System.out.println("[x] Sent '" + message + "'");
String message2 = "topics model message with key.1.2";
channel.basicPublish(EXCHANGE_NAME, "key.1.2", null, message2.getBytes());
System.out.println("[x] Sent '" + message2 + "'");
channel.close();
connection.close();
}
}
四种交换机介绍
1、直连交换机（Direct exchange）：
具有路由功能的交换机，绑定到此交换机的时候需要指定一个routing_key，交换机发送消息的时候需要routing_key，会将消息发送道对应的队列
2、扇形交换机（Fanout exchange）：
广播消息到所有队列，没有任何处理，速度最快，
3、主题交换机（Topic exchange）：
在直连交换机基础上增加模式匹配，也就是对routing_key进行模式匹配，*代表一个单词，#代表多个单词
4、首部交换机（Headers exchange）：
忽略routing_key，使用Headers信息（一个Hash的数据结构）进行匹配，优势在于可以有更多更灵活的匹配规则
总结
这么多种队列模式中都有其应用场景，大家可以根据应用场景示例中进行选择。另外，关注公众号互联网架构师，在后台回复：2T，可以获取我整理的 Java、MQ 系列面试题和答案，非常齐全。
原文链接：https://blog.csdn.net/qq_32828253/article/details/110450249
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