中间件-------RabbitMQ

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 {
    @Test
    public 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Channel
        Channel 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Channel
        Channel 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){
            @Override
            public 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: 192.168.136.132
    port: 5672
    username: itcast
    password: 123321
    virtual-host: /

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringAMQPTest {

    //获取RabbitTemplateAPI
    @Resource
    private RabbitTemplate rabbitTemplate;

    @Test
    public 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: 192.168.136.132
    port: 5672
    username: itcast
    password: 123321
    virtual-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
    @Resource
    private RabbitTemplate rabbitTemplate;

    @Test
    public 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: 192.168.136.132
    port: 5672
    username: itcast
    password: 123321
    virtual-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
    @Bean
    public FanoutExchange fanoutExchange(){
        return new FanoutExchange("itcast.fanout");
    }

    //声明队列1
    @Bean
    public Queue fanoutQueue1(){
        return new Queue("fanout.queue1");
    }
    //绑定队列1到交换机上
    @Bean
    public Binding fanoutBanding1(Queue fanoutQueue1,FanoutExchange fanoutExchange){
        return BindingBuilder
                .bind(fanoutQueue1)
                .to(fanoutExchange);
    }


    //声明队列2
    @Bean
    public Queue fanoutQueue2(){
        return new Queue("fanout.queue2");
    }
    //绑定队列2到交换机上
    @Bean
    public 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
    @Resource
    private RabbitTemplate rabbitTemplate;

    @Test
    public 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

    @Test
    public 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key
        rabbitTemplate.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
    @Resource
    private RabbitTemplate rabbitTemplate;

    @Test
    public 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>

@Bean
    public 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