1 引入依赖

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

2 配置Kafka

配置server、consumer
默认组id在config/consumer.properties文件下

# list of brokers used for bootstrapping knowledge about the rest of the cluster
# format: host1:port1,host2:port2 ...
bootstrap.servers=localhost:9092

# consumer group id
group.id=test-consumer-group

application.yml

spring:
  # kafaka
  kafka:
    bootstrap-servers: localhost:9092
    consumer:
      group-id: test-consumer-group
      enable-auto-commit: true # 自动提交
      auto-commit-interval: 3000 # 自动提交的频率（ms）

3 访问Kafaka

生产者主动发送消息，消费者被动处理消息。

KafkaTests.java

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;

@SpringBootTest
public class KafkaTests {

    @Autowired
    private KafkaProducer kafkaProducer;

    @Test
    public void testKafka() {
        kafkaProducer.sendMessage("test", "你好");
        kafkaProducer.sendMessage("test", "在吗");

        try {
            Thread.sleep(1000 * 10);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

// 生产者
@Component
class KafkaProducer {

    @Autowired
    private KafkaTemplate kafkaTemplate;

    public void sendMessage(String topic, String content) {
        kafkaTemplate.send(topic, content);
    }
}

// 消费者
@Component
class KafkaConsumer {

    @KafkaListener(topics = {"test"})
    public void handleMessage(ConsumerRecord record) {
        System.out.println(record.value());
    }
}