Spring-cloud-stream MessageConversionException

Question

我有一个接受@Payload 字符串的@StreamListener。 为了测试这个监听器 class，我使用嵌入式 Kafka 编写了 Junit class。 运行测试 class 时出现以下错误

错误

错误 osihandler.LoggingHandler - org.springframework.messaging.converter.MessageConversionException：GenericMessage 无法从 [[B] 转换为 [java.lang.String]

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如果我将 @Payload 的数据类型从 String 更改为 byte[]，我的监听器 class 会选择消息。

有人可以帮我知道这里的问题吗？ 我想这与云 stream 配置有关。

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@ExtendWith(SpringExtension.class)
@DirtiesContext
@SpringBootTest(classes = IntegrationTestConsumer.class)
@EmbeddedKafka(partitions = 1, controlledShutdown = true,
        topics = {
                "input",
                "output"})
public class TestUtils {

    public static final String KEY_SERIALIZER = "key.serializer";
    public static final String VALUE_SERIALIZER = "value.serializer";

    @Autowired
    private EmbeddedKafkaBroker embeddedKafka;

    @BeforeEach
    public void setup() {
        System.setProperty("spring.cloud.stream.kafka.binder.brokers", embeddedKafka.getBrokersAsString());
    }

    @Test
    public void someTest() throws Exception {
        Map<String, Object> senderProps = KafkaTestUtils.producerProps(embeddedKafka);
        senderProps.put(KEY_SERIALIZER, StringSerializer.class);
        senderProps.put(VALUE_SERIALIZER, StringSerializer.class);
        DefaultKafkaProducerFactory<String, String> producerFactory = new DefaultKafkaProducerFactory<>(senderProps);
        KafkaTemplate<String, String> template = new KafkaTemplate<>(producerFactory, true);
        template.setDefaultTopic("input");
        template.sendDefault("foo");

        Map<String, Object> consumerProps = KafkaTestUtils.consumerProps(
                "input_group",
                "false",
                this.embeddedKafka);
        consumerProps.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
        consumerProps.put("key.deserializer", StringDeserializer.class);
        consumerProps.put("value.deserializer", StringDeserializer.class);
        DefaultKafkaConsumerFactory<String, String> cf = new DefaultKafkaConsumerFactory<>(consumerProps);

        Consumer<String, String> consumer = cf.createConsumer();
        consumer.subscribe(Collections.singleton("output"));
        ConsumerRecords<String, String> records = consumer.poll(10_000);
        consumer.commitSync();
        Assertions.assertThat(records.count()).isGreaterThanOrEqualTo(1);

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这是我的应用程序。yaml 看起来像。

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 spring: cloud: stream: kafka: streams: binder: configuration: default: key: serde: org.apache.kafka.common.serialization.Serdes$StringSerde value: serde: org.apache.kafka.common.serialization.Serdes$StringSerde bindings: input: consumer: enable-dlq: true dlq-name: output dlq-producer-properties: retries: 1 binder: brokers: ${spring.embedded.kafka.brokers} replicationFactor: ${replication_factor:1} autoCreateTopics: true autoAddPartitions: true configuration: retries: 1 batch.size: 16384 linger.ms: 1 enable.idempotence: true buffer.memory: 33554432 request.timeout.ms: 3000 transaction.timeout.ms: 3000 max.block.ms: ${kafka_max_block_time:5000} max.poll.records: 80 poll.timeout: 10000 commit.retries: 1 commit.retry.interval: 1000 session.timeout.ms.config: 50000 shutdown.signal: INT,TERM acks: "all" bindings: output: destination: output contentType: application/json producer: partitionCount: ${partition_count:1} input: destination: input contentType: application/json partitioned: true group: input_group

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Answer 1

请检查您是否模拟了 ObjectMapper，因为 ObjectMapper 无法将 byte[] 转换为 String。

Answer 2

我的项目中也发生了类似的错误，开发人员是 mocking objectMapper，如果存在此类代码，请检查并删除 mocking。