[英]kafka - ERROR Error when sending message to topic test-topic with key: null, value: 17 bytes with error
[英]Error to serialize message when sending to kafka topic
我需要測試一條消息,其中包含標題,所以我需要使用 MessageBuilder,但我無法序列化。
我嘗試在 producer 道具上添加序列化設置,但它沒有用。
有人能幫我嗎?
這個錯誤:
org.apache.kafka.common.errors.SerializationException: Can't convert value of class org.springframework.messaging.support.GenericMessage to class org.apache.kafka.common.serialization.StringSerializer specified in value.serializer
我的測試class:
public class TransactionMastercardAdapterTest extends AbstractTest{
@Autowired
private KafkaTemplate<String, Message<String>> template;
@ClassRule
public static KafkaEmbedded embeddedKafka = new KafkaEmbedded(1);
@BeforeClass
public static void setUp() {
System.setProperty("spring.kafka.bootstrap-servers", embeddedKafka.getBrokersAsString());
System.setProperty("spring.cloud.stream.kafka.binder.zkNodes", embeddedKafka.getZookeeperConnectionString());
}
@Test
public void sendTransactionCommandTest(){
String payload = "{\"o2oTransactionId\" : \"" + UUID.randomUUID().toString().toUpperCase() + "\","
+ "\"cardId\" : \"11\","
+ "\"transactionId\" : \"20110405123456\","
+ "\"amount\" : 200.59,"
+ "\"partnerId\" : \"11\"}";
Map<String, Object> props = KafkaTestUtils.producerProps(embeddedKafka);
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
Producer<String, Message<String>> producer = new KafkaProducer<>(props);
producer.send(new ProducerRecord<String, Message<String>> ("notification_topic", MessageBuilder.withPayload(payload)
.setHeader("status", "RECEIVED")
.setHeader("service", "MASTERCARD")
.build()));
Map<String, Object> configs = KafkaTestUtils.consumerProps("test1", "false", embeddedKafka);
configs.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
ConsumerFactory<byte[], byte[]> cf = new DefaultKafkaConsumerFactory<>(configs);
Consumer<byte[], byte[]> consumer = cf.createConsumer();
consumer.subscribe(Collections.singleton("transaction_topic"));
ConsumerRecords<byte[], byte[]> records = consumer.poll(10_000);
consumer.commitSync();
assertThat(records.count()).isEqualTo(1);
}
}
我會說錯誤很明顯:
Can't convert value of class org.springframework.messaging.support.GenericMessage to class org.apache.kafka.common.serialization.StringSerializer specified in value.serializer
您的值是GenericMessage
,但StringSerializer
只能與字符串一起使用。
您需要的稱為JavaSerializer
,它不存在,但編寫起來並不難:
public class JavaSerializer implements Serializer<Object> {
@Override
public byte[] serialize(String topic, Object data) {
try {
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
ObjectOutputStream objectStream = new ObjectOutputStream(byteStream);
objectStream.writeObject(data);
objectStream.flush();
objectStream.close();
return byteStream.toByteArray();
}
catch (IOException e) {
throw new IllegalStateException("Can't serialize object: " + data, e);
}
}
@Override
public void configure(Map<String, ?> configs, boolean isKey) {
}
@Override
public void close() {
}
}
並為該value.serializer
屬性配置它。
private void configureProducer() {
Properties props = new Properties();
props.put("key.serializer",
"org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer",
"org.apache.kafka.common.serialization.ByteArraySerializer");
producer = new KafkaProducer<String, String>(props);
}
這將完成這項工作。
在我的情況下,我使用的是 spring cloud 並且沒有在屬性文件中添加以下屬性
spring.cloud.stream.kafka.binder.configuration.value.serializer=org.apache.kafka.common.serialization.StringSerializer
這是我用過的,對我有用
Map<String, Object> configProps = new HashMap<>();
configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, org.apache.kafka.common.serialization.StringSerializer.class);
configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, org.springframework.kafka.support.serializer.JsonSerializer.class);
spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.IntegerSerializer spring.kafka.producer.value-serializer=org.apache.kafka.common.StringSerialization.
使用@XmlRootElement
注釋 JSON 類
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