我用这个 Spring 启动Kafka来设置我的项目。但当我运行它时，它会 org.apache.kafka.common.errors.SerializationException: Can't convert key of class java.lang.Integer to class org.apache.kafka.common.serialization.StringSerializer specified in key.serializer Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String 使用kafka模板发送请求时出现此异常。

@EmbeddedKafka(partitions = 1)
@SpringBootTest
class KafkaApplicationTests {

    @Autowired
    private MyKafkaListener listener;

    @Autowired
    private KafkaTemplate<Integer, String> template;

    @Autowired
    private EmbeddedKafkaBroker embeddedKafka;

    @Test
    public void testSimple() throws Exception {
        template.send("annotated1", 0, "foo");
        template.flush();
        assertTrue(this.listener.latch1.await(10, TimeUnit.SECONDS));
    }

    @Configuration
    @EnableKafka
    public class Config {

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

        @Bean
        public ConsumerFactory<Integer, String> consumerFactory() {
            return new DefaultKafkaConsumerFactory<>(consumerConfigs());
        }

        @Bean
        public Map<String, Object> consumerConfigs() {
            Map<String, Object> props = new HashMap<>();
//          props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, embeddedKafka.getBrokersAsString());
            props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
            return props;
        }

        @Bean
        public ProducerFactory<Integer, String> producerFactory() {
            return new DefaultKafkaProducerFactory<>(producerConfigs());
        }

        @Bean
        public Map<String, Object> producerConfigs() {
            Map<String, Object> props = new HashMap<>();
            props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
            props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
//          props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, embeddedKafka.getBrokersAsString());
            props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
            return props;
        }

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

    }
}

但当我改变了这一点 template.send("annotated1", "key-foo", "foo"); 会有用的。我用过

@Bean
public Map<String, Object> producerConfigs() {
    Map<String, Object> props = new HashMap<>();
    props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
    props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
    props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    return props;
}

这种配置也是如此。但它仍然给我的原因是：java.lang.classcastexception:java.lang.integer不能转换为java.lang.string
如果有人在那里请帮助我。谢谢