如何将应用程序属性设置为默认的kafka producer模板，而不使用kafka producer配置bean进行设置

# Kafka配置
spring.kafka.bootstrap-servers=localhost:9092
spring.kafka.template.default-topic=mytopic

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;

@SpringBootApplication
public class KafkaProducerApplication {

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    public static void main(String[] args) {
        SpringApplication.run(KafkaProducerApplication.class, args);
    }

    public void sendMessage(String message) {
        Message<String> kafkaMessage = MessageBuilder
                .withPayload(message)
                .setHeader(KafkaHeaders.TOPIC, "mytopic")
                .build();
        kafkaTemplate.send(kafkaMessage);
    }
}