问题：
org.apache.kafka.common.KafkaException：构建kafka消费者失败
家西岭
我正在手动启动Zoomaster，然后是Kafka服务器，最后是Kafka-Rest服务器及其各自的属性文件。接下来，我正在tomcat上部署我的Spring Boot应用程序
在Tomcat日志跟踪中，我得到了错误org。springframework。上下文ApplicationContextException：无法启动bean的组织。springframework。Kafka。配置。internalKafkaListenerEndpointRegistry’；嵌套异常为org。阿帕奇。Kafka。常见的KafkaException：无法构造kafka使用者，我的应用程序无法启动
错误日志
25-Dec-2017 15:00:32.508 SEVERE [localhost-startStop-1] org.apache.catalina.core.ContainerBase.addChildInternal ContainerBase.addChild: start:
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/spring-kafka-webhook-service-0.0.1-SNAPSHOT]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:752)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:728)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:734)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:986)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.springframework.context.ApplicationContextException: Failed to start bean 'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is org.apache.kafka.common.KafkaException: Failed to construct kafka consumer
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178)
at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:50)
at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:348)
at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:151)
at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:114)
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:880)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:144)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
at org.springframework.boot.web.support.SpringBootServletInitializer.run(SpringBootServletInitializer.java:154)
at org.springframework.boot.web.support.SpringBootServletInitializer.createRootApplicationContext(SpringBootServletInitializer.java:134)
at org.springframework.boot.web.support.SpringBootServletInitializer.onStartup(SpringBootServletInitializer.java:87)
at org.springframework.web.SpringServletContainerInitializer.onStartup(SpringServletContainerInitializer.java:169)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5196)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 10 more
Caused by: org.apache.kafka.common.KafkaException: Failed to construct kafka consumer
at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:702)
at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:557)
at org.springframework.kafka.core.DefaultKafkaConsumerFactory.createKafkaConsumer(DefaultKafkaConsumerFactory.java:73)
at org.springframework.kafka.core.DefaultKafkaConsumerFactory.createConsumer(DefaultKafkaConsumerFactory.java:69)
at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.<init>(KafkaMessageListenerContainer.java:305)
at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.<init>(KafkaMessageListenerContainer.java:230)
at org.springframework.kafka.listener.KafkaMessageListenerContainer.doStart(KafkaMessageListenerContainer.java:180)
at org.springframework.kafka.listener.AbstractMessageListenerContainer.start(AbstractMessageListenerContainer.java:202)
at org.springframework.kafka.listener.ConcurrentMessageListenerContainer.doStart(ConcurrentMessageListenerContainer.java:126)
at org.springframework.kafka.listener.AbstractMessageListenerContainer.start(AbstractMessageListenerContainer.java:202)
at org.springframework.kafka.config.KafkaListenerEndpointRegistry.startIfNecessary(KafkaListenerEndpointRegistry.java:287)
at org.springframework.kafka.config.KafkaListenerEndpointRegistry.start(KafkaListenerEndpointRegistry.java:236)
at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:175)
... 27 more
Caused by: java.lang.NoClassDefFoundError: org/apache/kafka/common/ClusterResourceListener
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2283)
at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:811)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1260)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.kafka.common.utils.Utils.newInstance(Utils.java:332)
at org.apache.kafka.common.config.AbstractConfig.getConfiguredInstances(AbstractConfig.java:225)
at org.apache.kafka.clients.consumer.KafkaConsumer.<init>(KafkaConsumer.java:643)
... 39 more
Caused by: java.lang.ClassNotFoundException: org.apache.kafka.common.ClusterResourceListener
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1291)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
... 51 more
接收器类别
public class InventoryEventReceiver {
private static final Logger log = LoggerFactory.getLogger(InventoryEventReceiver.class);
private CountDownLatch latch = new CountDownLatch(1);
public CountDownLatch getLatch() {
return latch;
}
@KafkaListener(topics="inventory", containerFactory="kafkaListenerContainerFactory")
public void listenWithHeaders(
@Payload InventoryEvent event,
@Header(KafkaHeaders.RECEIVED_TOPIC) String topic,
@Header(KafkaHeaders.RECEIVED_MESSAGE_KEY) Integer key,
@Header(KafkaHeaders.RECEIVED_PARTITION_ID) int partition,
@Header(KafkaHeaders.OFFSET) String offset
) {
System.out.println("EVENT HAS BEEN RECEIVED by listenWithHeaders(InventoryEvent)");
System.out.println(event.toString());
log.info(System.currentTimeMillis() + "-- Received Event :\"" + event + "\" from partition:offset -- " + partition + ":" + offset +
" for topic : " + topic);
String urlForInventoryListeners = "http://localhost:8080/" + topic + "/listeners";
OutputStream os = null;
try {
URL objectUrl = new URL(urlForInventoryListeners);
HttpURLConnection con = (HttpURLConnection) objectUrl.openConnection();
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
con.setRequestProperty("topic", topic);
Gson gson = new Gson();
String eventJson = gson.toJson(event);
con.setDoOutput(true);
os = con.getOutputStream();
os.write(eventJson.getBytes("UTF-8"));
System.out.println("Event sent to " + objectUrl);
} catch (Exception e) {
e.printStackTrace();
System.out.println(e.getMessage());
} finally {
try {
os.close();
} catch (IOException e) {
e.printStackTrace();
System.out.println(e.getMessage());
}
}
latch.countDown();
}
}
接收器配置类
@Configuration
@EnableKafka
public class InventoryReceiverConfig {
@Autowired
private KafkaConfig kafkaConfig;
@Bean
public static ConsumerFactory<String, InventoryEvent> consumerFactory() {
return new DefaultKafkaConsumerFactory<>(consumerConfigs(), new StringDeserializer(),
new JsonDeserializer<>(InventoryEvent.class));
}
@Bean
public static ConcurrentKafkaListenerContainerFactory<String, InventoryEvent> kafkaListenerContainerFactory() {
ConcurrentKafkaListenerContainerFactory<String, InventoryEvent> containerFactory = new ConcurrentKafkaListenerContainerFactory<>();
containerFactory.setConsumerFactory(consumerFactory());
containerFactory.setConcurrency(3);
containerFactory.getContainerProperties().setPollTimeout(3000);
return containerFactory;
}
@Bean
public static Map<String, Object> consumerConfigs() {
Map<String, Object> consumerProps = new HashMap<>();
consumerProps.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
consumerProps.put(ConsumerConfig.GROUP_ID_CONFIG,"inventory_consumers");
consumerProps.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
consumerProps.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,JsonDeserializer.class);
consumerProps.put(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG, "io.confluent.monitoring.clients.interceptor.MonitoringConsumerInterceptor");
return consumerProps;
}
@Bean
public InventoryEventReceiver receiver() {
return new InventoryEventReceiver();
}
}
server.properties、consumer.properties和kafka-rest.properties的集群属性文件如下：
服务器属性
# The id of the broker. This must be set to a unique integer for each broker.
broker.id=0
# Switch to enable topic deletion or not, default value is false
delete.topic.enable=true
############################# Socket Server Settings #############################
# The address the socket server listens on. It will get the value returned from
# java.net.InetAddress.getCanonicalHostName() if not configured.
# FORMAT:
# listeners = listener_name://host_name:port
# EXAMPLE:
# listeners = PLAINTEXT://your.host.name:9092
listeners=PLAINTEXT://:9092
# Hostname and port the broker will advertise to producers and consumers. If not set,
# it uses the value for "listeners" if configured. Otherwise, it will use the value
# returned from java.net.InetAddress.getCanonicalHostName().
advertised.listeners=PLAINTEXT://localhost:9092
# The number of threads that the server uses for receiving requests from the network and sending responses to the network
num.network.threads=3
# The number of threads that the server uses for processing requests, which may include disk I/O
num.io.threads=8
# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=102400
# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=102400
# The maximum size of a request that the socket server will accept (protection against OOM)
socket.request.max.bytes=104857600
# A comma seperated list of directories under which to store log files
log.dirs=/tmp/kafka-logs
# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=1
# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
num.recovery.threads.per.data.dir=1
############################# Internal Topic Settings #############################
# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"
# For anything other than development testing, a value greater than 1 is recommended for to ensure availability such as 3.
offsets.topic.replication.factor=1
transaction.state.log.replication.factor=1
transaction.state.log.min.isr=1
# The minimum age of a log file to be eligible for deletion due to age
log.retention.hours=168
# The maximum size of a log segment file. When this size is reached a new log segment will be created.
log.segment.bytes=1073741824
# The interval at which log segments are checked to see if they can be deleted according
# to the retention policies
log.retention.check.interval.ms=300000
# Zookeeper connection string (see zookeeper docs for details).
# This is a comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".
# You can also append an optional chroot string to the urls to specify the
# root directory for all kafka znodes.
zookeeper.connect=localhost:2181
# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=6000
##################### Confluent Proactive Support ######################
# If set to true, and confluent-support-metrics package is installed
# then the feature to collect and report support metrics
# ("Metrics") is enabled. If set to false, the feature is disabled.
#
confluent.support.metrics.enable=true
############################# Group Coordinator Settings #############################
# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
group.initial.rebalance.delay.ms=0
# The customer ID under which support metrics will be collected and
# reported.
#
# When the customer ID is set to "anonymous" (the default), then only a
# reduced set of metrics is being collected and reported.
#
# Confluent customers
# -------------------
# If you are a Confluent customer, then you should replace the default
# value with your actual Confluent customer ID. Doing so will ensure
# that additional support metrics will be collected and reported.
#
confluent.support.customer.id=anonymous
消费者属性
# Zookeeper connection string
# comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"
zookeeper.connect=127.0.0.1:2181
# timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=6000
#consumer group id
group.id=test-consumer-group,inventory_consumers
#consumer timeout
#consumer.timeout.ms=5000
KafkaRest。属性
id=kafka-rest-test-server
schema.registry.url=http://localhost:8081
zookeeper.connect=localhost:2181
#
# Configure interceptor classes for sending consumer and producer metrics to Confluent Control Center
# Make sure that monitoring-interceptors-<version>.jar is on the Java class path
consumer.interceptor.classes=io.confluent.monitoring.clients.interceptor.MonitoringConsumerInterceptor
producer.interceptor.classes=io.confluent.monitoring.clients.interceptor.MonitoringProducerInterceptor
pom。xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.psl.kafka.spring</groupId>
<artifactId>spring-kafka-webhook-service</artifactId>
<packaging>war</packaging>
<name>spring-kafka-webhook-service</name>
<description>Spring Kafka Webhook Service</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<repositories>
<repository>
<id>confluent</id>
<url>http://packages.confluent.io/maven/</url>
</repository>
</repositories>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<org.springframework-version>5.0.0.RELEASE</org.springframework-version>
<org.springframework.security-version>4.0.1.RELEASE</org.springframework.security-version>
<org.aspectj-version>1.8.11</org.aspectj-version>
<org.slf4j-version>1.7.12</org.slf4j-version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>1.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka-test</artifactId>
<version>1.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.16</version>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.2</version>
<exclusions>
<exclusion>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
</exclusion>
<exclusion>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20160810</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.0</version>
</dependency>
<dependency>
<groupId>org.springframework.integration</groupId>
<artifactId>spring-integration-kafka</artifactId>
<version>2.1.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>0.10.0.1</version>
</dependency>
<dependency>
<groupId>io.confluent</groupId>
<artifactId>monitoring-interceptors</artifactId>
<version>3.1.1</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<version>0.0.1-SNAPSHOT</version>
</project>
我的Receiver和Sender类没有任何注释，例如组件或服务。这有什么区别吗？
@Configuration
public class InventorySenderConfig
@Configuration
@EnableKafka
public class InventoryReceiverConfig
@Component
public class KafkaConfig
@Configuration
public class ProducingChannelConfig
@Configuration
public class ConsumingChannelConfig
@RestController
public class KafkaWebhookController
@Service("webhookService")
public class KafkaServiceImpl
@EnableIntegration
@SpringBootApplication
@ComponentScan("com.psl.kafka")
public class SpringKafkaWebhookServiceApplication extends SpringBootServletInitializer
这些是我的类注释。它们看起来可以还是我需要更改一些东西？
新的构建错误后kafka版本更新到0.10.1.1
2017-12-26 13:11:44.490 INFO 13444 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka version : 0.10.1.1
2017-12-26 13:11:44.490 INFO 13444 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka commitId : f10ef2720b03b247
2017-12-26 13:12:44.499 ERROR 13444 --- [ main] o.s.k.support.LoggingProducerListener : Exception thrown when sending a message with key='inventory-events' and payload='Hello Spring Integration Kafka 0!' to topic inventory:
org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 60000 ms.
2017-12-26 13:12:44.501 WARN 13444 --- [ main] o.a.k.c.p.i.ProducerInterceptors : Error executing interceptor onAcknowledgement callback
java.lang.IllegalStateException: clusterResource is not defined
at io.confluent.shaded.com.google.common.base.Preconditions.checkState(Preconditions.java:174) ~[monitoring-interceptors-3.1.1.jar:na]
at io.confluent.monitoring.clients.interceptor.MonitoringProducerInterceptor.onAcknowledgement(MonitoringProducerInterceptor.java:59) ~[monitoring-interceptors-3.1.1.jar:na]
at org.apache.kafka.clients.producer.internals.ProducerInterceptors.onSendError(ProducerInterceptors.java:116) ~[kafka-clients-0.10.1.1.jar:na]
at org.apache.kafka.clients.producer.KafkaProducer.doSend(KafkaProducer.java:489) [kafka-clients-0.10.1.1.jar:na]
at org.apache.kafka.clients.producer.KafkaProducer.send(KafkaProducer.java:436) [kafka-clients-0.10.1.1.jar:na]
我是否需要定义我在ProducingChannelConfig、消费ChannelConfig以及InventoryReceiverConfig类中添加为配置的任何Interceptor类？
共有3个答案
姜奇
我在最近的一个项目中也遇到了这个错误。该错误也可能是由于缺少Kafka服务器。该应用程序正在尝试在application.properties文件中查找配置或服务器（PS：如果您不指定应用程序应从哪个配置文件加载，则您的应用程序将从application.properties加载）。
解决方案编辑您的配置（如果使用IntelliJ）并在程序参数中添加您添加Kafka引导服务器的配置文件。这样，当应用程序启动时，您已指定应用程序在包含Kafka引导服务器和详细信息的指定配置文件上运行。
--spring.profiles.active= <profile_name>
或者，如果您不想走这条漫长的路，只需创建一个application.properties文件而不指定任何配置文件，并在此属性文件中添加所有Kafka设置。它应该可以正常工作，因为默认情况下，应用程序运行application.properties.
东郭存
您的kafka版本比它应该的要旧，您有问题的类ClusterResourceListener期望版本高于0.10.1.0，而您的版本低于0.10.0.1。
只要升级你的Kafka罐子，它就会解决这个问题。
在每个元数据响应之后，将有一个onUpdate（ClusterResource）调用。请注意，当Kafka broker版本低于0.10.1.0时，集群id可能为null。
阎作人
原因：java.lang.ClassNotFoundException：org.apache.kafka.common.ClusterResourceListener
您的类路径中缺少kafka-Clientjar。您使用什么进行依赖管理？Maven和gradle应该自动将此jar放在类路径上。
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我有一个简单的Kafka设置。生成器正在以较高的速率向单个分区生成具有单个主题的消息。单个使用者正在使用来自此分区的消息。在此过程中，使用者可能会多次暂停处理消息。停顿可以持续几分钟。生产者停止产生消息后，所有排队的消息都将由使用者处理。生产者产生的消息似乎不会立即被消费者看到。我使用的是Kafka0.10.1.0。这里会发生什么？下面是使用消息的代码部分： 代理上的所有配置都保留为kafka默认
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假设我有一个服务，它通过kafka-rest-proxy来消费消息，并且总是在同一个消费者组上。我们还可以说，它正在消耗一个有一个分区的主题。当服务启动时，它在kafka-rest-proxy中创建一个新的使用者，并使用生成的使用者url，直到服务关闭。当服务重新启动时，它将在kafka-rest-proxy中创建一个新的消费者，并使用新的url（和新的消费者）进行消费。 > 因为kafka每个分
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我编写了一个spring kafka包，使用spring boot将消息发送到kafka主题，其中“Key”作为字符串，“Arraylist”作为值。“Custom Object”是一个具有属性item id、item name和item ordered count的类。 Kafka制作人日志如下所示。 我编写了一个自定义序列化程序，如下所示。 “Arraylist”的Serde类如下所示。 Ka