KafkaException：类不是 org.apache.kafka.common.serialization.Deserializer 的实例答案

【问题标题】：KafkaException: class is not an instance of org.apache.kafka.common.serialization.DeserializerKafkaException：类不是 org.apache.kafka.common.serialization.Deserializer 的实例
【发布时间】：2025-12-27 07:10:10
【问题描述】：

我想实现发送和接收 Java 序列化对象的 Kafka 生产者。我试过这个：

制片人：

@Configuration
public class KafkaProducerConfig {

@Value(value = "${kafka.bootstrapAddress}")
private String bootstrapAddress;

@Bean
public ProducerFactory<String, SaleRequestFactory> saleRequestFactoryProducerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, SaleRequestFactory.class);
    configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, SaleRequestFactory.class);
    return new DefaultKafkaProducerFactory<>(configProps);
}

@Bean
public ProducerFactory<String, String> producerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    /*
        Serialization configuration
     */
    return new DefaultKafkaProducerFactory<>(configProps);
}


@Bean
public KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate() {
    return new KafkaTemplate<>(saleRequestFactoryProducerFactory());
}

@Bean
public KafkaTemplate<String, String> kafkaTemplate() {
    return new KafkaTemplate<>(producerFactory());
}

}

发送对象：

@Autowired
private KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate;

private static String topic = "tp-sale";

private void perform(){

    SaleRequestFactory obj = new SaleRequestFactory();
    obj.setId(100);

    ListenableFuture<SendResult<String, SaleRequestFactory>> send = saleRequestFactoryKafkaTemplate.send(topic, obj);
}

消费者：

@EnableKafka
@Configuration
public class KafkaConsumerConfig {

    @Value(value = "${kafka.bootstrapAddress}")
    private String bootstrapAddress;

    private String groupId = "test";

    @Bean
    public ConsumerFactory<String, SaleResponseFactory> consumerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, SaleResponseFactory.class);
        return new DefaultKafkaConsumerFactory<>(props);
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> factory =
                new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());
        return factory;
    }
}

// 接收对象

    @KafkaListener(topics = "tp-sale")
public SaleResponseFactory transactionElavonAuthorizeProcess(@Payload SaleRequestFactory tf, @Headers MessageHeaders headers) throws Exception {

    System.out.println(tf.getId());

    SaleResponseFactory resObj = new SaleResponseFactory();
    resObj.setUnique_id("123123");

    return resObj;
}

当我部署 Producer 时，我在部署过程中遇到错误：

Caused by: org.apache.kafka.common.KafkaException: class org.engine.plugin.transactions.factory.SaleResponseFactory is not an instance of org.apache.kafka.common.serialization.Deserializer

自定义对象

import org.apache.kafka.common.serialization.Serializer;

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Builder(toBuilder = true)
public class SaleRequestFactory implements Serializable, Serializer {

    private static final long serialVersionUID = 1744050117179344127L;
    
    private int id;

    @Override
    public byte[] serialize(String s, Object o) {
        return new byte[0];
    }
}

导入 org.apache.kafka.common.serialization.Deserializer； @Getter @Setter @NoArgsConstructor @AllArgsConstructor @Builder(toBuilder = true) 公共类 SaleResponseFactory 实现可序列化、反序列化器 { 私有静态最终长序列版本UID = 1744050117179344127L；私有字符串 unique_id； @Override 公共对象反序列化（字符串 s，字节 [] 字节）{ 返回空值； } }

你知道我该如何解决这个问题吗？

编辑：我试过了：

制片人：

@Configuration
public class KafkaProducerConfig {

@Value(value = "${kafka.bootstrapAddress}")
private String bootstrapAddress;

@Bean
public ProducerFactory<String, SaleRequestFactory> saleRequestFactoryProducerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
    configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, SaleRequestFactorySerializer.class);
    return new DefaultKafkaProducerFactory<>(configProps);
}

@Bean
public ProducerFactory<String, String> producerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    return new DefaultKafkaProducerFactory<>(configProps);
}


@Bean
public KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate() {
    return new KafkaTemplate<>(saleRequestFactoryProducerFactory());
}

@Bean
public KafkaTemplate<String, String> kafkaTemplate() {
    return new KafkaTemplate<>(producerFactory());
}

}

发送对象：

@Autowired
private KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate;

private static String topic = "tp-sale";

private void perform(){

    SaleRequestFactory obj = new SaleRequestFactory();
    obj.setId(100);

    ListenableFuture<SendResult<String, SaleRequestFactory>> send = saleRequestFactoryKafkaTemplate.send(topic, obj);
}

消费者：

@EnableKafka
@Configuration
public class KafkaConsumerConfig {

    @Value(value = "${kafka.bootstrapAddress}")
    private String bootstrapAddress;

    private String groupId = "test";

    @Bean
    public ConsumerFactory<String, SaleResponseFactory> consumerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, SaleResponseFactoryDeserializer.class);
        return new DefaultKafkaConsumerFactory<>(props);
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> factory =
                new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());
        return factory;
    }
}

// 接收对象

    @KafkaListener(topics = "tp-sale")
public SaleResponseFactory transactionElavonAuthorizeProcess(@Payload SaleRequestFactory tf, @Headers MessageHeaders headers) throws Exception {

    System.out.println(tf.getId());

    SaleResponseFactory resObj = new SaleResponseFactory();
    resObj.setUnique_id("123123");

    return resObj;
}

自定义对象

    @Getter
    @Setter
    @NoArgsConstructor
    @AllArgsConstructor
    @Builder(toBuilder = true)
    public class SaleRequestFactory implements Serializable{
    
        private static final long serialVersionUID = 1744050117179344127L;
        
        private int id;
    }

public class SaleRequestFactorySerializer implements Serializable, Serializer<SaleRequestFactory> {

    @Override
    public byte[] serialize(String topic, SaleRequestFactory data) {
        // convert data to byte[]
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try
        {
            ObjectOutputStream outputStream = new ObjectOutputStream(out);
            outputStream.writeObject(data);
            out.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }

        return out.toByteArray();
    }
}


    @Getter
    @Setter
    @NoArgsConstructor
    @AllArgsConstructor
    @Builder(toBuilder = true)
    public class SaleResponseFactory implements Serializable{
    
        private static final long serialVersionUID = 1744050117179344127L;
    
        private String unique_id;
    }

public class SaleResponseFactoryDeserializer implements Serializable, Deserializer<SaleResponseFactory> {

    @Override
    public SaleResponseFactory deserialize(String topic, byte[] data) {
        // convert data to SaleResponseFactory
        SaleResponseFactory saleResponseFactory = null;
        try
        {
            ByteArrayInputStream bis = new ByteArrayInputStream(data);
            ObjectInputStream in = new ObjectInputStream(bis);
            saleResponseFactory = (SaleResponseFactory) in.readObject();
            in.close();
        }
        catch (IOException | ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        return saleResponseFactory;
    }
}

当我尝试发送消息时出现错误：

Caused by: org.apache.kafka.common.errors.SerializationException: Error deserializing key/value for partition tp-sale-0 at offset 0. If needed, please seek past the record to continue consumption.
Caused by: java.lang.ClassCastException: null
21:27:51.152 [org.springframework.kafka.KafkaListenerEndpointContainer#0-0-C-1] DEBUG KafkaMessageListenerContainer$ListenerConsumer[debug:296] - Commit list: {}
21:27:51.153 [org.springframework.kafka.KafkaListenerEndpointContainer#0-0-C-1] ERROR KafkaMessageListenerContainer$ListenerConsumer[error:149] - Consumer exception
java.lang.IllegalStateException: This error handler cannot process 'SerializationException's directly; please consider configuring an 'ErrorHandlingDeserializer' in the value and/or key deserializer
        at org.springframework.kafka.listener.SeekUtils.seekOrRecover(SeekUtils.java:145)
        at org.springframework.kafka.listener.SeekToCurrentErrorHandler.handle(SeekToCurrentErrorHandler.java:103)
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.handleConsumerException(KafkaMessageListenerContainer.java:1265)
        at org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer.run(KafkaMessageListenerContainer.java:1022)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.lang.Thread.run(Thread.java:835)
Caused by: org.apache.kafka.common.errors.SerializationException: Error deserializing key/value for partition tp-sale-0 at offset 0. If needed, please seek past the record to continue consumption.
Caused by: java.lang.ClassCastException: null

你知道我该如何解决这个问题吗？

编辑： 我设法实施了这些改进：

制片人：

@Configuration
public class KafkaProducerConfig {

@Value(value = "${kafka.bootstrapAddress}")
private String bootstrapAddress;

@Bean
public ProducerFactory<String, SaleRequestFactory> saleRequestFactoryProducerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
    configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, SaleRequestFactorySerializer.class);
    return new DefaultKafkaProducerFactory<>(configProps);
}

@Bean
public ProducerFactory<String, String> producerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
    return new DefaultKafkaProducerFactory<>(configProps);
}


@Bean
public KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate() {
    return new KafkaTemplate<>(saleRequestFactoryProducerFactory());
}

@Bean
public KafkaTemplate<String, String> kafkaTemplate() {
    return new KafkaTemplate<>(producerFactory());
}

}

发送对象：

@Autowired
private KafkaTemplate<String, SaleRequestFactory> saleRequestFactoryKafkaTemplate;

private static String topic = "tp-sale";

private void perform(){

    SaleRequestFactory obj = new SaleRequestFactory();
    obj.setId(100);

    ListenableFuture<SendResult<String, SaleRequestFactory>> send = saleRequestFactoryKafkaTemplate.send(topic, obj);
}

消费者：

@EnableKafka
@Configuration
public class KafkaConsumerConfig {

    @Value(value = "${kafka.bootstrapAddress}")
    private String bootstrapAddress;

    private String groupId = "test";

    @Bean
    public ConsumerFactory<String, SaleResponseFactory> consumerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapAddress);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, SaleResponseFactoryDeserializer.class);
        return new DefaultKafkaConsumerFactory<>(props);
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, SaleResponseFactory> factory =
                new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());
        return factory;
    }
}

接收对象

    @KafkaListener(topics = "tp-sale")
public SaleResponseFactory transactionElavonAuthorizeProcess(@Payload SaleRequestFactory tf, @Headers MessageHeaders headers) throws Exception {

    System.out.println(tf.getId());

    SaleResponseFactory resObj = new SaleResponseFactory();
    resObj.setUnique_id("123123");

    return resObj;
}

自定义对象

    @Getter
    @Setter
    @NoArgsConstructor
    @AllArgsConstructor
    @Builder(toBuilder = true)
    public class SaleRequestFactory implements Serializable{
    
        private static final long serialVersionUID = 1744050117179344127L;
        
        private int id;
    }

public class SaleRequestFactorySerializer implements Serializable, Serializer<SaleRequestFactory> {

    @Override
    public byte[] serialize(String topic, SaleRequestFactory data) {
        // convert data to byte[]
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try
        {
            ObjectOutputStream outputStream = new ObjectOutputStream(out);
            outputStream.writeObject(data);
            out.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }

        return out.toByteArray();
    }
}


    @Getter
    @Setter
    @NoArgsConstructor
    @AllArgsConstructor
    @Builder(toBuilder = true)
    public class SaleResponseFactory implements Serializable{
    
        private static final long serialVersionUID = 1744050117179344127L;
    
        private String unique_id;
    }

public class SaleResponseFactoryDeserializer implements Serializable, Deserializer<SaleResponseFactory> {

    @Override
    public SaleResponseFactory deserialize(String topic, byte[] data) {
        // convert data to SaleResponseFactory
        SaleResponseFactory saleResponseFactory = null;
        try
        {
            ByteArrayInputStream bis = new ByteArrayInputStream(data);
            ObjectInputStream in = new ObjectInputStream(bis);
            saleResponseFactory = (SaleResponseFactory) in.readObject();
            in.close();
        }
        catch (IOException | ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        return saleResponseFactory;
    }
}

当我发送一些消息时，我收到错误：

13:03:53.675 [org.springframework.kafka.KafkaListenerEndpointContainer#0-0-C-1] DEBUG RecordMessagingMessageListenerAdapter[debug:296] - Listener method returned result [org.factory.SaleResponseFactory@69c400ab] - generating response message for it
13:03:53.675 [org.springframework.kafka.KafkaListenerEndpointContainer#0-0-C-1] DEBUG RecordMessagingMessageListenerAdapter[debug:296] - No replyTopic to handle the reply: org.factory.SaleResponseFactory@69c400ab

你知道我该如何解决这个问题吗？

【问题讨论】：

这个回答你的问题吗？*.com/questions/16688655/…
您应该将被序列化的对象与实际的序列化程序类分开，它们不需要被称为“工厂”
你能给我看一下代码示例吗？
你已经有了它，但是修改命名SaleRequestSerializer implements org.apache.kafka.common.serialization.Serializer...我的意思是你的ProducerFactory，例如不应该“发送”你的序列化器，所以有一个单独的类ProducerFactory<String, SaleRequestFactory>

标签： java spring spring-boot apache-kafka spring-kafka

【解决方案1】：

您使用与序列化对象不同的类型来转换对象。不知道为什么你需要这样做。您可以将反序列化更新为如下所示。

public class SaleRequestFactoryDeserializer implements Serializable, Deserializer<SaleRequestFactory> {

     @Override
     public SaleRequestFactory deserialize(String topic, byte[] data) {
      ...
        saleRequestFactory = (SaleRequestFactory) in.readObject();

    }
}

java.lang.ClassCastException: null

这也意味着您的序列化没有按预期工作。在尝试投射之前，请确保您拥有有效的有效负载。

【讨论】：

这就是解决方案。另一个问题：我是否需要像这样添加刷新：ObjectOutputStream outputStream = new ObjectOutputStream(out); outputStream.writeObject(data); out.flush(); out.close(); 以防止内存泄漏？

【解决方案2】：

KEY_DESERIALIZER_CLASS_CONFIG 是一个将网络值反序列化为适当的 Java 类的类。您提供的课程没有这样做。

在大多数情况下，使用 StringDeserializer。为工厂属性指定适当的反序列化器。

【讨论】：

我更新了代码。现在我得到Caused by: org.apache.kafka.common.KafkaException: class org.engine.plugin.transactions.factory.SaleResponseFactory is not an instance of org.apache.kafka.common.serialization.Deserializer
"在大多数情况下，使用 StringDeserializer。" - 对于没有 toString 实现的自定义对象，这是错误的
你要么需要使用 Kafka 驱动提供的反序列化器，要么让你的类实现 org.apache.kafka.common.serialization.Deserializer。有关此接口的文档，请参阅 kafka.apache.org/21/javadoc/org/apache/kafka/common/…。