i need to test a message, which contains headers, so i need to use MessageBuilder, but I can not serialize.
I tried adding the serialization settings on the producer props but it did not work.
Can someone help me?
this error:
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
My test 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);
}
}
I'd say the error is obvious:
Can't convert value of class org.springframework.messaging.support.GenericMessage to class org.apache.kafka.common.serialization.StringSerializer specified in value.serializer
Where your value is GenericMessage
, but StringSerializer
can work only with strings.
What you need is called JavaSerializer
which does not exist, but not so difficult to write:
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() {
}
}
And configure it for that value.serializer
property.