展示一下springboot整合kafka示例代码

以下是一个简单的Spring Boot应用程序，演示了如何使用Kafka生产者和消费者。

1. 添加Kafka依赖

<dependency>
    <groupId>org.springframework.kafka</groupId>
    <artifactId>spring-kafka</artifactId>
</dependency>

2. 配置Kafka

spring:
  kafka:
    bootstrap-servers: localhost:9092
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer
    consumer:
      group-id: test-group
      auto-offset-reset: earliest
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

3. 编写Kafka生产者

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

@Service
public class KafkaProducer {
    private static final String TOPIC = "test-topic";

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    public void sendMessage(String message) {
        this.kafkaTemplate.send(TOPIC, message);
    }
}

4. 编写Kafka消费者

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Service;

@Service
public class KafkaConsumer {
    @KafkaListener(topics = "test-topic", groupId = "test-group")
    public void consume(String message) {
        System.out.println("Received message: " + message);
    }
}

5. 测试

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class KafkaDemoApplication implements CommandLineRunner {

    @Autowired
    private KafkaProducer kafkaProducer;

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

    @Override
    public void run(String... args) throws Exception {
        kafkaProducer.sendMessage("Hello, Kafka!");
    }
}

在运行应用程序后，将打印出接收到的消息。