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同步和异步

异步调用

MQ

MQ优势：①服务解耦   ②异步调用   ③流量削峰

结构

消息模型

 RabbitMQ入门案例，实现消息发送和消息接收

生产者：

public class PublisherTest {@Testpublic void testSendMessage() throws IOException, TimeoutException {// 1.建立连接ConnectionFactory factory = new ConnectionFactory();// 1.1.设置连接参数，分别是：主机名、端口号、vhost、用户名、密码factory.setHost("192.168.136.132");factory.setPort(5672);factory.setVirtualHost("/");factory.setUsername("itcast");factory.setPassword("123321");// 1.2.建立连接Connection connection = factory.newConnection();// 2.创建通道ChannelChannel channel = connection.createChannel();// 3.创建队列String queueName = "simple.queue";channel.queueDeclare(queueName, false, false, false, null);// 4.发送消息String message = "hello, rabbitmq!";channel.basicPublish("", queueName, null, message.getBytes());System.out.println("发送消息成功：【" + message + "】");// 5.关闭通道和连接channel.close();connection.close();}
}

消费者：

public class ConsumerTest {public static void main(String[] args) throws IOException, TimeoutException {// 1.建立连接ConnectionFactory factory = new ConnectionFactory();// 1.1.设置连接参数，分别是：主机名、端口号、vhost、用户名、密码factory.setHost("192.168.136.132");factory.setPort(5672);factory.setVirtualHost("/");factory.setUsername("itcast");factory.setPassword("123321");// 1.2.建立连接Connection connection = factory.newConnection();// 2.创建通道ChannelChannel channel = connection.createChannel();// 3.创建队列String queueName = "simple.queue";channel.queueDeclare(queueName, false, false, false, null);// 4.订阅消息channel.basicConsume(queueName, true, new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope,AMQP.BasicProperties properties, byte[] body) throws IOException {// 5.处理消息String message = new String(body);System.out.println("接收到消息：【" + message + "】");}});System.out.println("等待接收消息。。。。");}
}

SpringAMQP

引入依赖

        <!--AMQP依赖，包含RabbitMQ--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency>

---

普通队列 

 第一步：publisher服务配置文件，发消息

spring:rabbitmq:host: 192.168.136.132port: 5672username: itcastpassword: 123321virtual-host: /

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringAMQPTest {//获取RabbitTemplateAPI@Resourceprivate RabbitTemplate rabbitTemplate;@Testpublic void test(){String queueName = "simple.queue";String message = "hello SpringAMQP";//使用API传入队列名和消息即可直接发送rabbitTemplate.convertAndSend(queueName,message);}}

第二步：Consumer服务配置信息监听消息

spring:rabbitmq:host: 192.168.136.132port: 5672username: itcastpassword: 123321virtual-host: /

import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;//定义一个监听类去监听消息
@Component
public class SpringRabbitListener {@RabbitListener(queues = "simple.queue")public void ListenSimpleQueue(String msg){System.out.println("msg = " + msg);}
}

---

Work Queue队列

多个消费者绑定到同一个队列，可以通过prefetch来控制消费者消息预取的数量

第一步： 生产者发送消息

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringAMQPTest {//获取RabbitTemplateAPI@Resourceprivate RabbitTemplate rabbitTemplate;@Testpublic void test01() throws InterruptedException {String queueName = "simple.queue";String message = "hello SpringAMQP--";for (int i = 0; i < 50; i++) {//使用API传入队列名和消息即可直接发送rabbitTemplate.convertAndSend(queueName,message+i);Thread.sleep(20);}}}

第二步：消费者设置多个监听消息

@Component
public class SpringRabbitListener {@RabbitListener(queues = "simple.queue")public void ListenWorkQueue(String msg) throws InterruptedException {System.out.println("消费者一接收到消息---- = " + msg + LocalDateTime.now());Thread.sleep(20);}@RabbitListener(queues = "simple.queue")public void ListenWorkQueue01(String msg) throws InterruptedException {System.out.println("消费者二接收到消息---- = " + msg + LocalDateTime.now());Thread.sleep(200);}
}

 第三步：消费者可通过prehtch设置消息预取数量

spring:rabbitmq:host: 192.168.136.132port: 5672username: itcastpassword: 123321virtual-host: /listener:simple:prefetch: 1

---

发布-订阅模型

Fanout广播交换机 --->多个队列收到交换机的消息

第一步：Consumer声明交换机，队列并进行绑定。

@Configuration
public class FanoutConfig {//声明交换机@Beanpublic FanoutExchange fanoutExchange(){return new FanoutExchange("itcast.fanout");}//声明队列1@Beanpublic Queue fanoutQueue1(){return new Queue("fanout.queue1");}//绑定队列1到交换机上@Beanpublic Binding fanoutBanding1(Queue fanoutQueue1,FanoutExchange fanoutExchange){return BindingBuilder.bind(fanoutQueue1).to(fanoutExchange);}//声明队列2@Beanpublic Queue fanoutQueue2(){return new Queue("fanout.queue2");}//绑定队列2到交换机上@Beanpublic Binding fanoutBanding2(Queue fanoutQueue2,FanoutExchange fanoutExchange){return BindingBuilder.bind(fanoutQueue2).to(fanoutExchange);}
}

 第二步：Consumer进行监听消息

@Component
public class SpringRabbitListener {@RabbitListener(queues = "fanout.queue1")public void ListenSimpleQueue1(String msg){System.out.println("消费者接收到fanout.queue1的消息 = " + msg);}@RabbitListener(queues = "fanout.queue2")public void ListenSimpleQueue2(String msg){System.out.println("消费者接收到fanout.queue2的消息 = " + msg);}
}

第三步：Publisher向交换机发送消息

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringAMQPTest {//获取RabbitTemplateAPI@Resourceprivate RabbitTemplate rabbitTemplate;@Testpublic void testExchange() {//声明交换机名称String exchangeName = "itcast.fanout";//消息String message = "Hello Everyone";//发送消息rabbitTemplate.convertAndSend(exchangeName,"",message);}
}

Direct路由交换机 --->将消息发给指定key的队列

第一步：在Listener中声明队列，交换机以及key

@Component
public class SpringRabbitListener {//声明队列1，交换机以及队列1的bindingKey@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "derict.queue1"),exchange = @Exchange(name = "itcast.direct",type = ExchangeTypes.DIRECT),key = {"red","blue"}))public void ListenDirectQueue1(String msg){System.out.println("消费者接收到direct.queue1的消息 = " + msg);}//声明队列2，交换机以及队列2的bindingKey@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "derict.queue2"),exchange = @Exchange(name = "itcast.direct",type = ExchangeTypes.DIRECT),key = {"red","yellow"}))public void ListenDirectQueue2(String msg){System.out.println("消费者接收到direct.queue2的消息 = " + msg);}
}

第二步：向指定key的队列发送消息

    @Testpublic void testDirect() {//声明交换机名称String exchangeName = "itcast.direct";//消息String message = "Hello Blue！！";//发送消息，指定交换机，队列以及要发送的keyrabbitTemplate.convertAndSend(exchangeName,"red",message);}

Topic主题交换机 ---->key必须是多个单词列表，统一主题，支持通配符

 第一步：在Listener中声明队列，交换机以及通配符key

@Component
public class SpringRabbitListener {//声明队列2的交换机，队列以及通配符key@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "topic.queue1"),exchange = @Exchange(name = "itcast.topic",type = ExchangeTypes.TOPIC),key = "china.#"))public void ListenTopicQueue1(String msg){System.out.println("消费者接收到topic.queue1的消息 = " + msg);}//声明队列2的交换机，队列以及通配符key@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "topic.queue2"),exchange = @Exchange(name = "itcast.topic",type = ExchangeTypes.TOPIC),key = "#.news"))public void ListenTopicQueue2(String msg){System.out.println("消费者接收到topic.queue2的消息 = " + msg);}}

第二步：向主题通配符发送消息

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringAMQPTest {//获取RabbitTemplateAPI@Resourceprivate RabbitTemplate rabbitTemplate;@Testpublic void testTopic() {//声明交换机名称String exchangeName = "itcast.topic";//消息String message = "Hello China！！";//发送消息rabbitTemplate.convertAndSend(exchangeName,"china.news",message);}
}

消息转换器

 RabbitMQ发的消息体都是Object类型，所有还可以发送对象数据。而且默认的消息转换器是MessageConverter实现的，当使用的是Map数据类型时，就会序列化成很多字节，所以推荐使用JSON的序列化和反序列化，直接修改默认的MessageConverter的类型

        <dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId></dependency>

@Beanpublic MessageConverter messageConverter(){return  new Jackson2JsonMessageConverter();}

对于RabbitMQ高级部分：死信队列，延迟队列，发布确认，幂等性，优先，惰性队列等有时间再学