Spring Cloud Stream的配置及使用——以RabbitMQ为例

1. 简介

https://docs.spring.io/spring-cloud-stream-binder-rabbit/docs/current/reference/html/spring-cloud-stream-binder-rabbit.html
英语好的可以直接看官方文档，文档里讲的更全面

By default, the RabbitMQ Binder implementation maps each destination to a TopicExchange. For each consumer group, a Queue is bound to that TopicExchange.

上图是RabbitMQ Binder(绑定器)。默认情况下，绑定器实现将每一个destination映射到一个TopicExchange。对于每一个消费者组，都有一个队列绑定到那个TopicExchange。

2. 依赖配置

<dependency>
    <groupId>org.springframework.cloudgroupId>
    <artifactId>spring-cloud-dependenciesartifactId>
    <version>${spring-cloud.version}version>
    <type>pomtype>
    <scope>importscope>
dependency>
<dependency>
    <groupId>org.springframework.cloudgroupId>
    <artifactId>spring-cloud-starter-stream-rabbitartifactId>
dependency>

3. 生产者配置及消息发送

3.1 yaml配置

spring:
  cloud:
    stream:
      #      如果有一个binder的话,就不需要设置
      default-binder: rabbit
      binders:
        rabbit1:
          type: rabbit
          environment:
            spring:
              rabbitmq:
                host: 192.168.70.224
                port: 5672
                username: admin
                password: 444944
                virtual-host: GHost
        rabbit:
          type: rabbit
          defaultCandidate: false
          environment:
            spring:
              rabbitmq:
                host: 192.168.70.167
                port: 5672
                username: admin
                password: public
                virtual-host: /
      bindings:
        order:
          binder: rabbit
          destination: order
          producer:
            #            默认是true
            autoStartup: true
        cart:
          binder: rabbit
          destination: cart
          routingKeyExpression: han
          producer:
            #            默认是true
            autoStartup: true
# rabbitmq发送的消息默认routingKey为destination, 如果是分区的destination, 默认值为destination-

配置说明：

• 在Spring Cloud Stream中可以配置多个binder，也就是可以配置连接多个MQ服务器
• 在RabbitMQ中，binding的名称对应的是output和input的名称，destination对应mq中的exchange名称。上述配置会生成order，cart两个exchange
• rabbitmq发送的消息默认routingKey为destination, 如果是分区的destination, 默认值为destination-，分区内容这里不涉及，具体内容看官方文档

3.2 生产者声明

public interface CartSource {
    /**
     * Name of the output channel.
     * cart对应的是binding,
     * destination对应的是rabbitmq里的exchange,kafka中的topic.
     * 如果没有设置destination, rabbitmq会自动创建一个和binding同名的exchange
     */
    String OUTPUT = "cart";

    /**
     * @return output channel
     */
    @Output(CartSource.OUTPUT)
    MessageChannel output();
}

cloud stream中output表示发送，这里的cart与配置中的binding名称是对应的

//必须添加，要不然无法注入。也可以加在启动类上，可以重复添加
@EnableBinding(CartSource.class)
@Component
public class CartSender {

    @Autowired
    private CartSource orderSource;

    private static final Logger logger= LoggerFactory.getLogger(CartSender.class);

    public void pushMsg(Order order){
        logger.info("sending rabbitmq message:{}",order.toString());
        orderSource.output().send(MessageBuilder.withPayload(order).build());
    }

3.3 消息发送

@RestController
@RequestMapping("mqTest1")
public class MqTest1Controller {
    @Autowired
    CartSender cartSender;
    @GetMapping("streamPush")
    public String streamPush(){
        cartSender.pushMsg(new Order());
        return "hehe";
    }
}

4. 消费者配置

4.1 yaml配置

spring:
  cloud:
    stream:
      #      如果有一个binder的话,就不需要设置
      default-binder: rabbit
      binders:
        rabbit1:
          type: rabbit
          environment:
            spring:
              rabbitmq:
                host: 192.168.70.224
                port: 5672
                username: admin
                password: 444944
                virtual-host: /
        rabbit:
          type: rabbit
          defaultCandidate: false
          environment:
            spring:
              rabbitmq:
                host: 192.168.70.167
                port: 5672
                username: admin
                password: public
                virtual-host: /
      bindings:
        order:
          binder: rabbit
          destination: order
          group: myOrderQueue
          conumer:
            concurrency: 3
        cart:
          binder: rabbit
          destination: cart
          group: myCartQueue
          conumer:
            concurrency: 3
      # rabbit的扩展配置 RabbitExtendedBindingProperties
      rabbit:
        bindings:
#          order:
#            consumer:
#              bindingRoutingKey: order-key
          cart:
            consumer:
              #          如果没有指定routing key,会使用默认的 #
              bindingRoutingKey: cart-key

配置说明：

• 只有消费者才会创建队列，queue名称为：.
• routingKey设置
  spring.cloud.stream.rabbit.bindings..consumer.bindingRoutingKey=myRoutingKey
  如果没有设置的话，默认为#

4.2 消费者声明与消息接收

public interface CartSink {

    String INPUT = "cart";

    /**
     * @return input channel.
     */
    @Input(CartSink.INPUT)
    SubscribableChannel input();
}

cloud stream中input表示接收，这里的cart与配置中的binding名称是对应的

@EnableBinding(CartSink.class)
public class CartHandler {
    private static final Logger logger = LoggerFactory.getLogger(CartHandler.class);
    /**
     * 参数也可以是对象，会自动将消息转换为对象
     * @param headers
     * @param payload
     */
    @StreamListener(CartSink.INPUT)
    public void loggerSink(@Headers MessageHeaders headers, byte[] payload){
        String cartChange=new String(payload);
        logger.info("cart change:{}",cartChange);
    }
}