Question

这是我的应用程序，它仅从客户主题（输入绑定）获取一个KStream的引用，而从订单主题（订单绑定）获取另一个的KStream。然后，它根据客户主题创建一个KTable，并按订单KStream执行联接：

@Configuration
class ShippingKStreamConfiguration {


    @StreamListener
    @SendTo("output")
    fun process(@Input("input") input: KStream<Int, Customer>, @Input("order") order: KStream<Int, Order>): KStream<Int, OrderShipped> {

        val intSerde = Serdes.IntegerSerde()
        val customerSerde = JsonSerde<Customer>(Customer::class.java)
        val orderSerde = JsonSerde<Order>(Order::class.java)

        val stateStore: Materialized<Int, Customer, KeyValueStore<Bytes, ByteArray>> =
                Materialized.`as`<Int, Customer, KeyValueStore<Bytes, ByteArray>>("customer-store")
                        .withKeySerde(intSerde)
                        .withValueSerde(customerSerde)

        val customerTable: KTable<Int, Customer> = input.groupByKey(Serialized.with(intSerde, customerSerde))
                .reduce({ _, y -> y }, stateStore)

        return (order.selectKey { key, value -> value.customerId } as KStream<Int, Order>)
                .join(customerTable, { orderIt, customer ->
                    OrderShipped(orderIt.id)
                },
                        Joined.with(intSerde, orderSerde, customerSerde))

    }

}

假设这应该写入到输出绑定（@SendTo("output")），并指向订购主题。但是，没有消息写到该主题。

处理器配置：

interface ShippingKStreamProcessor {

    @Input("input")
    fun input(): KStream<Int, Customer>

    @Input("order")
    fun order(): KStream<String, Order>

    @Input("output")
    fun output(): KStream<String, OrderShipped>

}

**application.yml**

spring:
  application:
    name: spring-boot-shipping-service
  cloud:
    stream:
      kafka:
        streams:
          binder:
            configuration:
              default:
                key:
                  serde: org.apache.kafka.common.serialization.Serdes$IntegerSerde
                value:
                  serde: org.apache.kafka.common.serialization.Serdes$StringSerde
      bindings:
        input:
          destination: customer
          contentType: application/json
        order:
          destination: order
          contentType: application/json
        output:
          destination: ordershipments
          contentType: application/json

Answer 1

处理器定义错误，这是使用@Output而非@Input的好方法：

interface ShippingKStreamProcessor {

    @Input("input")
    fun input(): KStream<Int, Customer>

    @Input("order")
    fun order(): KStream<String, Order>

    @Output("output")
    fun output(): KStream<String, OrderShipped>

}

加入后Spring Cloud Stream Kafka Stream无法写入目标主题

1 个答案: