Question

我有一个主题可以从中接收不同类型的json。但是，似乎在消费者尝试读取消息时出现异常。我尝试添加其他bean名称，但是没有用。似乎它试图从该主题中读取并尝试转换为从该主题中读取的所有类型。有没有一种方法可以指定只为特定的输入类型启用特定的工厂。还有其他方法可以解决此问题。

错误

原因： org.springframework.messaging.converter.MessageConversionException：无法转换 [com.lte.assessment.assesssments.AssessmentAttemptRequest]至 [com.lte.assessmentanalytics.data.SiteLevelAnalyticsRequest]用于通用消息 [payload=com.lte.assessment.assesssments.AssessmentAttemptRequest@68eb637f，标头= {kafka_offset = 22， kafka_consumer=org.apache.kafka.clients.consumer.KafkaConsumer@252d8ffb， kafka_timestampType = CREATE_TIME，kafka_receivedMessageKey =空， kafka_receivedPartitionId = 0，kafka_receivedTopic = ltetopic， kafka_receivedTimestamp = 1546117529267}

配置

@EnableKafka
@Configuration
public class KafkaConfig {
    static Map<String, Object> config = new HashMap();

    static {
        config.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "127.0.0.1:9092");
        config.put(ConsumerConfig.GROUP_ID_CONFIG, "group_id");
        config.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        config.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);
    }


    @Bean
    public ConsumerFactory<String, AssessmentAttemptRequest> assessmentAttemptDetailsEntityConsumerFactory() {
        JsonDeserializer<AssessmentAttemptRequest> deserializer = new JsonDeserializer<>();
        deserializer.addTrustedPackages("com.lte.assessment.assessments");
        return new DefaultKafkaConsumerFactory(config, new StringDeserializer(), deserializer);
    }

    @Bean(name="aaKafkaListenerFactory")
    public ConcurrentKafkaListenerContainerFactory aaKafkaListenerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, AssessmentAttemptRequest> factory = new ConcurrentKafkaListenerContainerFactory();
        factory.setConsumerFactory(assessmentAttemptDetailsEntityConsumerFactory());
        return factory;
    }

    @Bean
    public ConsumerFactory<String, AssessmentQuestionAnalyticsEntity> assessmentQuestionAnalyticssEntityConsumerFactory() {
        JsonDeserializer<AssessmentQuestionAnalyticsEntity> deserializer = new JsonDeserializer<>();
        deserializer.addTrustedPackages("com.lte.assessment.assessments");
        return new DefaultKafkaConsumerFactory(config, new StringDeserializer(), deserializer);
    }

    @Bean(name="aqKafkaListenerFactory")
    public ConcurrentKafkaListenerContainerFactory aqKafkaListenerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, AssessmentQuestionAnalyticsEntity> factory = new ConcurrentKafkaListenerContainerFactory();
        factory.setConsumerFactory(assessmentQuestionAnalyticssEntityConsumerFactory());
        return factory;
    }

    @Bean
    public ConsumerFactory<String, SiteLevelAnalyticsEntity> siteLevelAnalyticsEntityConsumerFactory() {
        JsonDeserializer<SiteLevelAnalyticsEntity> deserializer = new JsonDeserializer<>();
        deserializer.addTrustedPackages("com.lte.assessment.assessments");
        return new DefaultKafkaConsumerFactory(config, new StringDeserializer(), deserializer);
    }

    @Bean("slaKafkaListenerFactory")
    public ConcurrentKafkaListenerContainerFactory slaKafkaListenerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, SiteLevelAnalyticsEntity> factory = new ConcurrentKafkaListenerContainerFactory();
        factory.setConsumerFactory(siteLevelAnalyticsEntityConsumerFactory());
        return factory;
    }
}

服务

@Service
public class TopicObserver implements
        ConsumerSeekAware.ConsumerSeekCallback,ConsumerSeekAware{

    @Autowired
    private AssessmentAttemptService assessmentAttemptService;

    @Autowired
    private AssessmentQuestionService assessmentQuestionService;

    @Autowired
    private SiteLevelAnalyticsService siteLevelAnalyticsService;

    private final ThreadLocal<ConsumerSeekCallback> seekCallBack = new ThreadLocal<>();

    @KafkaListener(topics = "ltetopic", groupId = "group_id", containerFactory = "aaKafkaListenerFactory")
    public void consumeAttemptDetails(AssessmentAttemptRequest request) {
        assessmentAttemptService.storeAttempDetails(request);
    }

    @KafkaListener(topics = "ltetopic", groupId = "group_id", containerFactory = "aqKafkaListenerFactory")
    public void setAssessmentQeustionAnalytics(AssessmentQuestionRequest request) {
        assessmentQuestionService.storeQuestionDetails(request);
    }

    @KafkaListener(topics = "ltetopic", groupId = "group_id", containerFactory = "slaKafkaListenerFactory")
    public void siteLevelAnalytics(SiteLevelAnalyticsRequest request) {
        siteLevelAnalyticsService.storeSiteLevelDetailsDetails(request);
    }
}

Answer 1

@Bean
public ConsumerFactory<String, SiteLevelAnalyticsEntity> siteLevelAnalyticsEntityConsumerFactory() {
    JsonDeserializer<SiteLevelAnalyticsEntity> deserializer = new JsonDeserializer<>();
    deserializer.addTrustedPackages("com.lte.assessment.assessments");
    return new DefaultKafkaConsumerFactory(config, new StringDeserializer(), deserializer);
}

在消费工厂中，您分配了SiteLevelAnalyticsEntity，而JsonDeserializer是评估包。请定义-deserializer.addTrustedPackages("com.lte.assessment.SiteLevelAnalyticsEntity");

Answer 2

@Deadpool是正确的。如果需要更简单的解决方案，请将消息作为String JSON有效负载使用，然后手动将其反序列化为对象。

        @Bean
        public ConsumerFactory<Integer, String> createConsumerFactory() {
            Map<String, Object> props = new HashMap<>();
            props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, 
              kafkaEmbedded().getBrokersAsString());
            props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
            props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
            props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
            return new DefaultKafkaConsumerFactory<>(props);
        }

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

在您的侦听器中，以String形式使用。

@KafkaListener(id = "foo", topics = YOUR_TOPIC)
    public void listen(String json){
    //Convert to Object here.
}

如何从kafka springboot中的一个主题读取多种类型的json

2 个答案: