配置props.put(ProducerConfig.PARTITIONER_CLASS_CONFIG, RoundRobinPartitioner.class);

public Map<String,Object> producerConfigs(){
    Map<String,Object> props = new HashMap<>();
    props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,bootstrapServers);
    props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,valueSerializer);
    props.put(ProducerConfig.PARTITIONER_CLASS_CONFIG, RoundRobinPartitioner.class);
    return props;
}

public ProducerFactory producerFactory(){
    return new DefaultKafkaProducerFactory<>(producerConfigs());
}

// 覆盖spring-kafka中的配置
@Bean
public KafkaTemplate<String,Object> kafkaTemplate(){
    return new KafkaTemplate<String,Object>(producerFactory());
}