春季启动kafka hello world应用程序无法以“无法将属性绑定到...到...”开头

Question

我正在使用this教程尝试基本的Spring Boot kafka应用程序。

我的项目层次结构如下：

SpringBootKafkaApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

KafkaController.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.temp.kafka_springboot_pocs.services.Producer;

@RestController
@RequestMapping(value = "/kafka")
public class KafkaController {

    private final Producer producer;

    @Autowired
    public KafkaController(Producer producer) {
        this.producer = producer;
    }

    @PostMapping(value = "/publish")
    public void sendMessageToKafkaTopic(@RequestParam("message") String message) {
        this.producer.sendMessage(message);
    }
}

Consumer.java

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;

@Service
public class Consumer {

    private final Logger logger = LoggerFactory.getLogger(Consumer.class);

    @KafkaListener(topics = "kafka_poc_3", groupId = "group_id")
    public void consume(String message) {
        logger.info(String.format("$$ -> Consumed Message -> %s", message));
    }
}

Producer.java

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Service;

@Service
public class Producer {

    private static final Logger logger = LoggerFactory.getLogger(Producer.class);
    private static final String TOPIC = "kafka_poc_3";

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    public void sendMessage(String message) {
        logger.info(String.format("$$ -> Producing message --> %s",message));
        this.kafkaTemplate.send(TOPIC, message);
    }
}

application.properties

spring.kafka.bootstrap-servers=localhost:9092

spring.kafka.consumer.group-id=group-1
spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserialize

spring.kafka.producer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.producer.value-deserializer=org.apache.kafka.common.serialization.StringDeserialize

Spring Boot应用程序无法启动并显示以下错误描述：

说明：

Failed to bind properties under 'spring.kafka.consumer.value-deserializer' to java.lang.Class<?>:

    Property: spring.kafka.consumer.value-deserializer
    Value: org.apache.kafka.common.serialization.StringDeserialize
    Origin: class path resource [application.properties]:12:42
    Reason: No converter found capable of converting from type [java.lang.String] to type [java.lang.Class<?>]

我在这里想念的是什么？

PS：我在春季和春季靴子上工作了很长时间。所以会爱一个给我一个好的方向的人，或者给出示例或确切答案的链接。

Answer 1

尝试使用此属性

#KAFKA生产商设置

spring.kafka.producer.key-serializer = org.apache.kafka.common.serialization.StringSerializer spring.kafka.producer.value-serializer = org.apache.kafka.common.serialization.StringSerializer

#KAFKA消费者设置

spring.kafka.consumer.key-deserializer = org.apache.kafka.common.serialization.StringDeserializer spring.kafka.consumer.value-deserializer = org.apache.kafka.common.serialization.StringDeserializer spring.kafka.consumer.auto-offset-reset =最早