(window.webpackJsonp=window.webpackJsonp||[]).push([[474],{906:function(e,a,n){"use strict";n.r(a);var r=n(56),t=Object(r.a)({},(function(){var e=this,a=e.$createElement,n=e._self._c||a;return n("ContentSlotsDistributor",{attrs:{"slot-key":e.$parent.slotKey}},[n("h1",{attrs:{id:"apache-kafka-支持"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#apache-kafka-支持"}},[e._v("#")]),e._v(" Apache Kafka 支持")]),e._v(" "),n("h2",{attrs:{id:"apache-kafka-支持-2"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#apache-kafka-支持-2"}},[e._v("#")]),e._v(" Apache Kafka 支持")]),e._v(" "),n("h3",{attrs:{id:"概述"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#概述"}},[e._v("#")]),e._v(" 概述")]),e._v(" "),n("p",[e._v("Spring Apache Kafka 的集成基于"),n("a",{attrs:{href:"https://projects.spring.io/spring-kafka/",target:"_blank",rel:"noopener noreferrer"}},[e._v("Spring for Apache Kafka project"),n("OutboundLink")],1),e._v("。")]),e._v(" "),n("p",[e._v("你需要在项目中包含此依赖项：")]),e._v(" "),n("p",[e._v("Maven")]),e._v(" 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             e -> e.id("kafkaProducer1")))\n                    .subscribe(sf -> sf.handle(\n                            kafkaMessageHandler(producerFactory(), TEST_TOPIC2)\n                                   .timestamp(m -> 1487694048644L),\n                            e -> e.id("kafkaProducer2")))\n            );\n}\n\n@Bean\npublic DefaultKafkaHeaderMapper mapper() {\n    return new DefaultKafkaHeaderMapper();\n}\n\nprivate KafkaProducerMessageHandlerSpec<Integer, String, ?> kafkaMessageHandler(\n        ProducerFactory<Integer, String> producerFactory, String topic) {\n    return Kafka\n            .outboundChannelAdapter(producerFactory)\n            .messageKey(m -> m\n                    .getHeaders()\n                    .get(IntegrationMessageHeaderAccessor.SEQUENCE_NUMBER))\n            .headerMapper(mapper())\n            .partitionId(m -> 10)\n            .topicExpression("headers[kafka_topic] ?: \'" + topic + "\'")\n            .configureKafkaTemplate(t -> t.id("kafkaTemplate:" + topic));\n}\n')])])]),n("h4",{attrs:{id:"xml-配置"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 XML 配置 Kafka 出站通道适配器：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:outbound-channel-adapter id="kafkaOutboundChannelAdapter"\n                                    kafka-template="template"\n                                    auto-startup="false"\n                                    channel="inputToKafka"\n                                    topic="foo"\n                                    sync="false"\n                                    message-key-expression="\'bar\'"\n                                    send-failure-channel="failures"\n                                    send-success-channel="successes"\n                                    error-message-strategy="ems"\n                                    partition-id-expression="2">\n</int-kafka:outbound-channel-adapter>\n\n<bean id="template" class="org.springframework.kafka.core.KafkaTemplate">\n    <constructor-arg>\n        <bean class="org.springframework.kafka.core.DefaultKafkaProducerFactory">\n            <constructor-arg>\n                <map>\n                    <entry key="bootstrap.servers" value="localhost:9092" />\n                    ... \x3c!-- more producer properties --\x3e\n                </map>\n            </constructor-arg>\n        </bean>\n    </constructor-arg>\n</bean>\n')])])]),n("h3",{attrs:{id:"消息驱动通道适配器"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#消息驱动通道适配器"}},[e._v("#")]),e._v(" 消息驱动通道适配器")]),e._v(" "),n("p",[n("code",[e._v("KafkaMessageDrivenChannelAdapter")]),e._v("（"),n("code",[e._v("<int-kafka:message-driven-channel-adapter>")]),e._v("）使用"),n("code",[e._v("spring-kafka``KafkaMessageListenerContainer")]),e._v("或"),n("code",[e._v("ConcurrentListenerContainer")]),e._v("。")]),e._v(" 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ListenerMode.record);\n    kafkaMessageDrivenChannelAdapter.setOutputChannel(received());\n    return kafkaMessageDrivenChannelAdapter;\n}\n\n@Bean\npublic KafkaMessageListenerContainer<String, String> container() throws Exception {\n    ContainerProperties properties = new ContainerProperties(this.topic);\n    // set more properties\n    return new KafkaMessageListenerContainer<>(consumerFactory(), properties);\n}\n\n@Bean\npublic ConsumerFactory<String, String> consumerFactory() {\n    Map<String, Object> props = new HashMap<>();\n    props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, this.brokerAddress);\n    // set more properties\n    return new DefaultKafkaConsumerFactory<>(props);\n}\n")])])]),n("h4",{attrs:{id:"java-dsl-配置-2"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-dsl-配置-2"}},[e._v("#")]),e._v(" Java DSL 配置")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 Spring 集成 Java DSL 配置消息驱动通道适配器：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow topic1ListenerFromKafkaFlow() {\n    return IntegrationFlows\n            .from(Kafka.messageDrivenChannelAdapter(consumerFactory(),\n                    KafkaMessageDrivenChannelAdapter.ListenerMode.record, TEST_TOPIC1)\n                    .configureListenerContainer(c ->\n                            c.ackMode(AbstractMessageListenerContainer.AckMode.MANUAL)\n                                    .id("topic1ListenerContainer"))\n                    .recoveryCallback(new ErrorMessageSendingRecoverer(errorChannel(),\n                            new RawRecordHeaderErrorMessageStrategy()))\n                    .retryTemplate(new RetryTemplate())\n                    .filterInRetry(true))\n            .filter(Message.class, m ->\n                            m.getHeaders().get(KafkaHeaders.RECEIVED_MESSAGE_KEY, Integer.class) < 101,\n                    f -> f.throwExceptionOnRejection(true))\n            .<String, String>transform(String::toUpperCase)\n            .channel(c -> c.queue("listeningFromKafkaResults1"))\n            .get();\n}\n')])])]),n("p",[e._v("还可以使用用于"),n("code",[e._v("@KafkaListener")]),e._v("注释的容器工厂为其他目的创建"),n("code",[e._v("ConcurrentMessageListenerContainer")]),e._v("实例。有关示例，请参见"),n("a",{attrs:{href:"https://docs.spring.io/spring-kafka/docs/current/reference/html/",target:"_blank",rel:"noopener noreferrer"}},[e._v("the Spring for Apache Kafka documentation"),n("OutboundLink")],1),e._v("。")]),e._v(" "),n("p",[e._v("对于 Java DSL，容器不必配置为"),n("code",[e._v("@Bean")]),e._v("，因为 DSL 将容器注册为 Bean。下面的示例展示了如何做到这一点：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow topic2ListenerFromKafkaFlow() {\n    return IntegrationFlows\n            .from(Kafka.messageDrivenChannelAdapter(kafkaListenerContainerFactory().createContainer(TEST_TOPIC2),\n            KafkaMessageDrivenChannelAdapter.ListenerMode.record)\n                .id("topic2Adapter"))\n            ...\n            get();\n}\n')])])]),n("p",[e._v("注意，在这种情况下，适配器被赋予"),n("code",[e._v("id")]),e._v("（"),n("code",[e._v("topic2Adapter")]),e._v("）。容器以"),n("code",[e._v("topic2Adapter.container")]),e._v("的名称注册在应用程序上下文中。如果适配器没有"),n("code",[e._v("id")]),e._v("属性，则容器的 Bean 名称是容器的完全限定类名称加上"),n("code",[e._v("#n")]),e._v("，其中"),n("code",[e._v("n")]),e._v("对每个容器递增。")]),e._v(" "),n("h4",{attrs:{id:"xml-配置-2"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置-2"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 XML 配置消息驱动的通道适配器：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:message-driven-channel-adapter\n        id="kafkaListener"\n        listener-container="container1"\n        auto-startup="false"\n        phase="100"\n        send-timeout="5000"\n        mode="record"\n        retry-template="template"\n        recovery-callback="callback"\n        error-message-strategy="ems"\n        channel="someChannel"\n        error-channel="errorChannel" />\n\n<bean id="container1" class="org.springframework.kafka.listener.KafkaMessageListenerContainer">\n    <constructor-arg>\n        <bean class="org.springframework.kafka.core.DefaultKafkaConsumerFactory">\n            <constructor-arg>\n                <map>\n                <entry key="bootstrap.servers" value="localhost:9092" />\n                ...\n                </map>\n            </constructor-arg>\n        </bean>\n    </constructor-arg>\n    <constructor-arg>\n        <bean class="org.springframework.kafka.listener.config.ContainerProperties">\n            <constructor-arg name="topics" value="foo" />\n        </bean>\n    </constructor-arg>\n\n</bean>\n')])])]),n("h3",{attrs:{id:"入站通道适配器"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#入站通道适配器"}},[e._v("#")]),e._v(" 入站通道适配器")]),e._v(" "),n("p",[n("code",[e._v("KafkaMessageSource")]),e._v("提供了一个可匹配的通道适配器实现。")]),e._v(" "),n("h4",{attrs:{id:"java-配置-3"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-配置-3"}},[e._v("#")]),e._v(" Java 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@InboundChannelAdapter(channel = "fromKafka", poller = @Poller(fixedDelay = "5000"))\n@Bean\npublic KafkaMessageSource<String, String> source(ConsumerFactory<String, String> cf)  {\n    KafkaMessageSource<String, String> source = new KafkaMessageSource<>(cf, "myTopic");\n    source.setGroupId("myGroupId");\n    source.setClientId("myClientId");\n    return source;\n}\n')])])]),n("p",[e._v("请参考 Javadocs 以获得可用的属性。")]),e._v(" "),n("p",[e._v("默认情况下，"),n("code",[e._v("max.poll.records")]),e._v("必须在消费工厂中显式设置，或者如果消费工厂是"),n("code",[e._v("DefaultKafkaConsumerFactory")]),e._v("，则将强制设置为 1。可以将属性"),n("code",[e._v("allowMultiFetch")]),e._v("设置为"),n("code",[e._v("true")]),e._v("以覆盖此行为。")]),e._v(" "),n("table",[n("thead",[n("tr",[n("th"),e._v(" "),n("th",[e._v("你必须在"),n("code",[e._v("max.poll.interval.ms")]),e._v("内轮询消费者以避免重新平衡。"),n("br"),e._v("如果你将"),n("code",[e._v("allowMultiFetch")]),e._v("设置为"),n("code",[e._v("true")]),e._v("，你必须处理所有检索到的记录，并在"),n("code",[e._v("max.poll.interval.ms")]),e._v("内再次轮询。")])])]),e._v(" "),n("tbody")]),e._v(" "),n("p",[e._v("此适配器发出的消息包含一个标题"),n("code",[e._v("kafka_remainingRecords")]),e._v("，其中包含上一个轮询中剩余的记录的计数。")]),e._v(" "),n("h4",{attrs:{id:"java-dsl-配置-3"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-dsl-配置-3"}},[e._v("#")]),e._v(" Java DSL 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow flow(ConsumerFactory<String, String> cf)  {\n    return IntegrationFlows.from(Kafka.inboundChannelAdapter(cf, "myTopic")\n                .groupId("myDslGroupId"), e -> e.poller(Pollers.fixedDelay(5000)))\n            .handle(System.out::println)\n            .get();\n}\n')])])]),n("h4",{attrs:{id:"xml-配置-3"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置-3"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:inbound-channel-adapter\n        id="adapter1"\n        consumer-factory="consumerFactory"\n        ack-factory="ackFactory"\n        topics="topic1"\n        channel="inbound"\n        client-id="client"\n        group-id="group"\n        message-converter="converter"\n        payload-type="java.lang.String"\n        raw-header="true"\n        auto-startup="false"\n        rebalance-listener="rebal">\n    <int:poller fixed-delay="5000"/>\n</int-kafka:inbound-channel-adapter>\n')])])]),n("h3",{attrs:{id:"出站网关"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#出站网关"}},[e._v("#")]),e._v(" 出站网关")]),e._v(" "),n("p",[e._v("出站网关用于请求/回复操作。它与大多数 Spring 集成网关的不同之处在于，发送线程不会在网关中阻塞，而应答将在应答侦听器容器线程上进行处理。如果你的代码调用同步"),n("a",{attrs:{href:"https://docs.spring.io/spring-integration/reference/html/messaging-endpoints-chapter.html#gateway",target:"_blank",rel:"noopener noreferrer"}},[e._v("消息传递网关"),n("OutboundLink")],1),e._v("后面的网关，则用户线程将在此阻塞，直到收到答复（或者发生超时）。")]),e._v(" "),n("table",[n("thead",[n("tr",[n("th"),e._v(" "),n("th",[e._v("网关不接受请求，直到应答容器分配了它的主题和分区。"),n("br"),e._v("建议你在模板的应答容器属性中添加"),n("code",[e._v("ConsumerRebalanceListener")]),e._v("，并在向网关发送消息之前等待"),n("code",[e._v("onPartitionsAssigned")]),e._v("调用。")])])]),e._v(" "),n("tbody")]),e._v(" "),n("p",[n("code",[e._v("KafkaProducerMessageHandler``sendTimeoutExpression")]),e._v("默认值是"),n("code",[e._v("delivery.timeout.ms")]),e._v("Kafka Producer 属性"),n("code",[e._v("+ 5000")]),e._v("，这样超时后的实际 Kafka 错误将传播到应用程序，而不是由该框架生成的超时。为了保持一致性，对此进行了更改，因为你可能会遇到意外的行为（ Spring 可能会超时发送，而实际上最终是成功的）。重要提示：默认情况下，超时时间为 120 秒，因此你可能希望减少超时时间，以获得更多的及时故障。")]),e._v(" "),n("h4",{attrs:{id:"java-配置-4"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-配置-4"}},[e._v("#")]),e._v(" Java 配置")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 Java 配置网关：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\n@ServiceActivator(inputChannel = "kafkaRequests", outputChannel = "kafkaReplies")\npublic KafkaProducerMessageHandler<String, String> outGateway(\n        ReplyingKafkaTemplate<String, String, String> kafkaTemplate) {\n    return new KafkaProducerMessageHandler<>(kafkaTemplate);\n}\n')])])]),n("p",[e._v("请参考 Javadocs 以获得可用的属性。")]),e._v(" "),n("p",[e._v("请注意，使用了与"),n("a",{attrs:{href:"#kafka-outbound"}},[e._v("出站通道适配器")]),e._v("相同的类，唯一的区别是传递到构造函数的"),n("code",[e._v("KafkaTemplate")]),e._v("是"),n("code",[e._v("ReplyingKafkaTemplate")]),e._v("。有关更多信息，请参见"),n("a",{attrs:{href:"https://docs.spring.io/spring-kafka/docs/current/reference/html/",target:"_blank",rel:"noopener noreferrer"}},[e._v("the Spring for Apache Kafka documentation"),n("OutboundLink")],1),e._v("。")]),e._v(" "),n("p",[e._v("出站主题、分区、键等都是以与出站适配器相同的方式确定的。答复题目确定如下：")]),e._v(" "),n("ol",[n("li",[n("p",[e._v("一个名为"),n("code",[e._v("KafkaHeaders.REPLY_TOPIC")]),e._v("的消息头（如果存在，它必须具有"),n("code",[e._v("String")]),e._v("或"),n("code",[e._v("byte[]")]),e._v("值）将根据模板的回复容器的订阅主题进行验证。")])]),e._v(" "),n("li",[n("p",[e._v("如果模板的"),n("code",[e._v("replyContainer")]),e._v("仅订阅了一个主题，则使用该主题。")])])]),e._v(" "),n("p",[e._v("还可以指定"),n("code",[e._v("KafkaHeaders.REPLY_PARTITION")]),e._v("头，以确定用于答复的特定分区。同样，这是根据模板的回复容器的订阅进行验证的。")]),e._v(" "),n("h4",{attrs:{id:"java-dsl-配置-4"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-dsl-配置-4"}},[e._v("#")]),e._v(" Java DSL 配置")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 Java DSL 配置出站网关：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow outboundGateFlow(\n        ReplyingKafkaTemplate<String, String, String> kafkaTemplate) {\n\n    return IntegrationFlows.from("kafkaRequests")\n            .handle(Kafka.outboundGateway(kafkaTemplate))\n            .channel("kafkaReplies")\n            .get();\n}\n')])])]),n("p",[e._v("或者，也可以使用类似于以下 Bean 的配置：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow outboundGateFlow() {\n    return IntegrationFlows.from("kafkaRequests")\n            .handle(Kafka.outboundGateway(producerFactory(), replyContainer())\n                .configureKafkaTemplate(t -> t.replyTimeout(30_000)))\n            .channel("kafkaReplies")\n            .get();\n}\n')])])]),n("h4",{attrs:{id:"xml-配置-4"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置-4"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:outbound-gateway\n    id="allProps"\n    error-message-strategy="ems"\n    kafka-template="template"\n    message-key-expression="\'key\'"\n    order="23"\n    partition-id-expression="2"\n    reply-channel="replies"\n    reply-timeout="43"\n    request-channel="requests"\n    requires-reply="false"\n    send-success-channel="successes"\n    send-failure-channel="failures"\n    send-timeout-expression="44"\n    sync="true"\n    timestamp-expression="T(System).currentTimeMillis()"\n    topic-expression="\'topic\'"/>\n')])])]),n("h3",{attrs:{id:"入站网关"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#入站网关"}},[e._v("#")]),e._v(" 入站网关")]),e._v(" "),n("p",[e._v("入站网关用于请求/回复操作。")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 Java 配置入站网关：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v("@Bean\npublic KafkaInboundGateway<Integer, String, String> inboundGateway(\n        AbstractMessageListenerContainer<Integer, String>container,\n        KafkaTemplate<Integer, String> replyTemplate) {\n\n    KafkaInboundGateway<Integer, String, String> gateway =\n        new KafkaInboundGateway<>(container, replyTemplate);\n    gateway.setRequestChannel(requests);\n    gateway.setReplyChannel(replies);\n    gateway.setReplyTimeout(30_000);\n    return gateway;\n}\n")])])]),n("p",[e._v("请参考 Javadocs 以获得可用的属性。")]),e._v(" "),n("p",[e._v("下面的示例展示了如何使用 Java DSL 配置一个简单的大写转换器：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v("@Bean\npublic IntegrationFlow serverGateway(\n        ConcurrentMessageListenerContainer<Integer, String> container,\n        KafkaTemplate<Integer, String> replyTemplate) {\n    return IntegrationFlows\n            .from(Kafka.inboundGateway(container, replyTemplate)\n                .replyTimeout(30_000))\n            .<String, String>transform(String::toUpperCase)\n            .get();\n}\n")])])]),n("p",[e._v("或者，你可以通过使用类似于以下代码来配置大写转换器：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v("@Bean\npublic IntegrationFlow serverGateway() {\n    return IntegrationFlows\n            .from(Kafka.inboundGateway(consumerFactory(), containerProperties(),\n                    producerFactory())\n                .replyTimeout(30_000))\n            .<String, String>transform(String::toUpperCase)\n            .get();\n}\n")])])]),n("p",[e._v("还可以使用用于"),n("code",[e._v("@KafkaListener")]),e._v("注释的容器工厂为其他目的创建"),n("code",[e._v("ConcurrentMessageListenerContainer")]),e._v("实例。有关示例，请参见"),n("a",{attrs:{href:"https://docs.spring.io/spring-kafka/docs/current/reference/html/",target:"_blank",rel:"noopener noreferrer"}},[e._v("the Spring for Apache Kafka documentation"),n("OutboundLink")],1),e._v("和"),n("a",{attrs:{href:"#kafka-inbound"}},[e._v("消息驱动通道适配器")]),e._v("。")]),e._v(" "),n("h4",{attrs:{id:"xml-配置-5"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置-5"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:inbound-gateway\n        id="gateway1"\n        listener-container="container1"\n        kafka-template="template"\n        auto-startup="false"\n        phase="100"\n        request-timeout="5000"\n        request-channel="nullChannel"\n        reply-channel="errorChannel"\n        reply-timeout="43"\n        message-converter="messageConverter"\n        payload-type="java.lang.String"\n        error-message-strategy="ems"\n        retry-template="retryTemplate"\n        recovery-callback="recoveryCallback"/>\n')])])]),n("p",[e._v("有关每个属性的描述，请参见 XML 模式。")]),e._v(" "),n("h3",{attrs:{id:"由-apache-kafka-主题支持的通道"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#由-apache-kafka-主题支持的通道"}},[e._v("#")]),e._v(" 由 Apache Kafka 主题支持的通道")]),e._v(" "),n("p",[e._v("Spring 集成具有"),n("code",[e._v("MessageChannel")]),e._v("实现，该实现由用于持久性的 Apache Kafka 主题支持。")]),e._v(" "),n("p",[e._v("每个通道都需要一个"),n("code",[e._v("KafkaTemplate")]),e._v("用于发送端，或者一个侦听器容器工厂（用于可订阅通道），或者一个"),n("code",[e._v("KafkaMessageSource")]),e._v("用于可检索通道。")]),e._v(" "),n("h4",{attrs:{id:"java-dsl-配置-5"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-dsl-配置-5"}},[e._v("#")]),e._v(" Java DSL 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic IntegrationFlow flowWithSubscribable(KafkaTemplate<Integer, String> template,\n        ConcurrentKafkaListenerContainerFactory<Integer, String> containerFactory) {\n\n    return IntegrationFlows.from(...)\n            ...\n            .channel(Kafka.channel(template, containerFactory, "someTopic1").groupId("group1"))\n            ...\n            .get();\n}\n\n@Bean\npublic IntegrationFlow flowWithPubSub(KafkaTemplate<Integer, String> template,\n        ConcurrentKafkaListenerContainerFactory<Integer, String> containerFactory) {\n\n    return IntegrationFlows.from(...)\n            ...\n            .publishSubscribeChannel(pubSub(template, containerFactory),\n                pubsub -> pubsub\n                            .subscribe(subflow -> ...)\n                            .subscribe(subflow -> ...))\n            .get();\n}\n\n@Bean\npublic BroadcastCapableChannel pubSub(KafkaTemplate<Integer, String> template,\n        ConcurrentKafkaListenerContainerFactory<Integer, String> containerFactory) {\n\n    return Kafka.publishSubscribeChannel(template, containerFactory, "someTopic2")\n            .groupId("group2")\n            .get();\n}\n\n@Bean\npublic IntegrationFlow flowWithPollable(KafkaTemplate<Integer, String> template,\n        KafkaMessageSource<Integer, String> source) {\n\n    return IntegrationFlows.from(...)\n            ...\n            .channel(Kafka.pollableChannel(template, source, "someTopic3").groupId("group3"))\n            .handle(...,  e -> e.poller(...))\n            ...\n            .get();\n}\n')])])]),n("h4",{attrs:{id:"java-配置-5"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#java-配置-5"}},[e._v("#")]),e._v(" Java 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('/**\n * Channel for a single subscriber.\n **/\n@Bean\nSubscribableKafkaChannel pointToPoint(KafkaTemplate<String, String> template,\n    KafkaListenerContainerFactory<String, String> factory)\n\n    SubscribableKafkaChannel channel =\n        new SubscribableKafkaChannel(template, factory, "topicA");\n    channel.setGroupId("group1");\n    return channel;\n}\n\n/**\n * Channel for multiple subscribers.\n **/\n@Bean\nSubscribableKafkaChannel pubsub(KafkaTemplate<String, String> template,\n    KafkaListenerContainerFactory<String, String> factory)\n\n    SubscribableKafkaChannel channel =\n        new SubscribableKafkaChannel(template, factory, "topicB", true);\n    channel.setGroupId("group2");\n    return channel;\n}\n\n/**\n * Pollable channel (topic is configured on the source)\n **/\n@Bean\nPollableKafkaChannel pollable(KafkaTemplate<String, String> template,\n    KafkaMessageSource<String, String> source)\n\n    PollableKafkaChannel channel =\n        new PollableKafkaChannel(template, source);\n    channel.setGroupId("group3");\n    return channel;\n}\n')])])]),n("h4",{attrs:{id:"xml-配置-6"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#xml-配置-6"}},[e._v("#")]),e._v(" XML 配置")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:channel kafka-template="template" id="ptp" topic="ptpTopic" group-id="ptpGroup"\n    container-factory="containerFactory" />\n\n<int-kafka:pollable-channel kafka-template="template" id="pollable" message-source="source"\n    group-id = "pollableGroup"/>\n\n<int-kafka:publish-subscribe-channel kafka-template="template" id="pubSub" topic="pubSubTopic"\n    group-id="pubSubGroup" container-factory="containerFactory" />\n')])])]),n("h3",{attrs:{id:"消息转换"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#消息转换"}},[e._v("#")]),e._v(" 消息转换")]),e._v(" "),n("p",[e._v("a"),n("code",[e._v("StringJsonMessageConverter")]),e._v("。有关更多信息，请参见"),n("a",{attrs:{href:"https://docs.spring.io/spring-kafka/docs/current/reference/html/",target:"_blank",rel:"noopener noreferrer"}},[e._v("the Spring for Apache Kafka documentation"),n("OutboundLink")],1),e._v("。")]),e._v(" "),n("p",[e._v("当将此转换器与消息驱动通道适配器一起使用时，你可以指定要将传入的有效负载转换为哪种类型。这是通过在适配器上设置"),n("code",[e._v("payload-type")]),e._v("属性（"),n("code",[e._v("payloadType")]),e._v("属性）来实现的。下面的示例展示了如何在 XML 配置中实现这一点：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('<int-kafka:message-driven-channel-adapter\n        id="kafkaListener"\n        listener-container="container1"\n        auto-startup="false"\n        phase="100"\n        send-timeout="5000"\n        channel="nullChannel"\n        message-converter="messageConverter"\n        payload-type="com.example.Foo"\n        error-channel="errorChannel" />\n\n<bean id="messageConverter"\n    class="org.springframework.kafka.support.converter.MessagingMessageConverter"/>\n')])])]),n("p",[e._v("下面的示例展示了如何在 Java 配置中设置适配器上的"),n("code",[e._v("payload-type")]),e._v("属性（"),n("code",[e._v("payloadType")]),e._v("属性）：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v("@Bean\npublic KafkaMessageDrivenChannelAdapter<String, String>\n            adapter(KafkaMessageListenerContainer<String, String> container) {\n    KafkaMessageDrivenChannelAdapter<String, String> kafkaMessageDrivenChannelAdapter =\n            new KafkaMessageDrivenChannelAdapter<>(container, ListenerMode.record);\n    kafkaMessageDrivenChannelAdapter.setOutputChannel(received());\n    kafkaMessageDrivenChannelAdapter.setMessageConverter(converter());\n    kafkaMessageDrivenChannelAdapter.setPayloadType(Foo.class);\n    return kafkaMessageDrivenChannelAdapter;\n}\n")])])]),n("h3",{attrs:{id:"空有效载荷和日志压缩-墓碑-记录"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#空有效载荷和日志压缩-墓碑-记录"}},[e._v("#")]),e._v(" 空有效载荷和日志压缩“墓碑”记录")]),e._v(" "),n("p",[e._v("Spring 消息传递"),n("code",[e._v("Message<?>")]),e._v("对象不能具有"),n("code",[e._v("null")]),e._v("有效负载。当你使用 Apache Kafka 的端点时，"),n("code",[e._v("null")]),e._v("有效载荷（也称为 Tombstone 记录）由类型为"),n("code",[e._v("KafkaNull")]),e._v("的有效载荷表示。有关更多信息，请参见"),n("a",{attrs:{href:"https://docs.spring.io/spring-kafka/docs/current/reference/html/",target:"_blank",rel:"noopener noreferrer"}},[e._v("the Spring for Apache Kafka documentation"),n("OutboundLink")],1),e._v("。")]),e._v(" "),n("p",[e._v("Spring 集成端点的 POJO 方法可以使用真正的"),n("code",[e._v("null")]),e._v("值，而不是"),n("code",[e._v("KafkaNull")]),e._v("值。要这样做，用"),n("code",[e._v("@Payload(required = false)")]),e._v("标记参数。下面的示例展示了如何做到这一点：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@ServiceActivator(inputChannel = "fromSomeKafkaInboundEndpoint")\npublic void in(@Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) String key,\n               @Payload(required = false) Customer customer) {\n    // customer is null if a tombstone record\n    ...\n}\n')])])]),n("h3",{attrs:{id:"从kstream调用-spring-集成流"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#从kstream调用-spring-集成流"}},[e._v("#")]),e._v(" 从"),n("code",[e._v("KStream")]),e._v("调用 Spring 集成流")]),e._v(" "),n("p",[e._v("你可以使用"),n("code",[e._v("MessagingTransformer")]),e._v("从"),n("code",[e._v("KStream")]),e._v("调用集成流：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@Bean\npublic KStream<byte[], byte[]> kStream(StreamsBuilder kStreamBuilder,\n        MessagingTransformer<byte[], byte[], byte[]> transformer)  transformer) {\n    KStream<byte[], byte[]> stream = kStreamBuilder.stream(STREAMING_TOPIC1);\n    stream.mapValues((ValueMapper<byte[], byte[]>) String::toUpperCase)\n            ...\n            .transform(() -> transformer)\n            .to(streamingTopic2);\n\n    stream.print(Printed.toSysOut());\n\n    return stream;\n}\n\n@Bean\n@DependsOn("flow")\npublic MessagingTransformer<byte[], byte[], String> transformer(\n        MessagingFunction function) {\n\n    MessagingMessageConverter converter = new MessagingMessageConverter();\n    converter.setHeaderMapper(new SimpleKafkaHeaderMapper("*"));\n    return new MessagingTransformer<>(function, converter);\n}\n\n@Bean\npublic IntegrationFlow flow() {\n    return IntegrationFlows.from(MessagingFunction.class)\n        ...\n        .get();\n}\n')])])]),n("p",[e._v("当一个集成流从一个接口开始时，所创建的代理具有该流的名称 Bean，并附加了“.gateway”，因此如果需要，这个 Bean 名称可以使用 a"),n("code",[e._v("@Qualifier")]),e._v("。")]),e._v(" "),n("h3",{attrs:{id:"读-处理-写场景的性能注意事项"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#读-处理-写场景的性能注意事项"}},[e._v("#")]),e._v(" 读/处理/写场景的性能注意事项")]),e._v(" "),n("p",[e._v("许多应用程序使用一个主题，执行一些处理并写入另一个主题。在大多数情况下，如果写入失败，应用程序将希望抛出一个异常，以便可以重试传入的请求并/或将其发送到一个死信主题。该功能由底层消息侦听器容器以及适当配置的错误处理程序支持。然而，为了支持这一点，我们需要阻塞侦听器线程，直到写操作成功（或失败），以便可以将任何异常抛到容器中。当使用单个记录时，可以通过在出站适配器上设置"),n("code",[e._v("sync")]),e._v("属性来实现。然而，当使用批处理时，使用"),n("code",[e._v("sync")]),e._v("会导致显著的性能下降，因为应用程序将在发送下一条消息之前等待每次发送的结果。你还可以执行多个发送，然后等待这些发送的结果。这是通过向消息处理程序添加"),n("code",[e._v("futuresChannel")]),e._v("来实现的。要启用该功能，请将"),n("code",[e._v("KafkaIntegrationHeaders.FUTURE_TOKEN")]),e._v("添加到出站消息中；然后可以使用此功能将"),n("code",[e._v("Future")]),e._v("关联到特定的已发送消息。下面是一个如何使用此功能的示例：")]),e._v(" "),n("div",{staticClass:"language- extra-class"},[n("pre",{pre:!0,attrs:{class:"language-text"}},[n("code",[e._v('@SpringBootApplication\npublic class FuturesChannelApplication {\n\n    public static void main(String[] args) {\n        SpringApplication.run(FuturesChannelApplication.class, args);\n    }\n\n    @Bean\n    IntegrationFlow inbound(ConsumerFactory<String, String> consumerFactory, Handler handler) {\n        return IntegrationFlows.from(Kafka.messageDrivenChannelAdapter(consumerFactory,\n                    ListenerMode.batch, "inTopic"))\n                .handle(handler)\n                .get();\n    }\n\n    @Bean\n    IntegrationFlow outbound(KafkaTemplate<String, String> kafkaTemplate) {\n        return IntegrationFlows.from(Gate.class)\n                .enrichHeaders(h -> h\n                        .header(KafkaHeaders.TOPIC, "outTopic")\n                        .headerExpression(KafkaIntegrationHeaders.FUTURE_TOKEN, "headers[id]"))\n                .handle(Kafka.outboundChannelAdapter(kafkaTemplate)\n                        .futuresChannel("futures"))\n                .get();\n    }\n\n    @Bean\n    PollableChannel futures() {\n        return new QueueChannel();\n    }\n\n}\n\n@Component\n@DependsOn("outbound")\nclass Handler {\n\n    @Autowired\n    Gate gate;\n\n    @Autowired\n    PollableChannel futures;\n\n    public void handle(List<String> input) throws Exception {\n        System.out.println(input);\n        input.forEach(str -> this.gate.send(str.toUpperCase()));\n        for (int i = 0; i < input.size(); i++) {\n            Message<?> future = this.futures.receive(10000);\n            ((Future<?>) future.getPayload()).get(10, TimeUnit.SECONDS);\n        }\n    }\n\n}\n\ninterface Gate {\n\n    void send(String out);\n\n}\n')])])])])}),[],!1,null,null,null);a.default=t.exports}}]);