在springboot项目中引入Kafka

第一步：在web下的pom文件中引入依赖

<!--kafka-->
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
            <version>2.7.8</version>
        </dependency>

第二步：在配置文件中引入kafka

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

第三步：创建一个生产者

package com.qcby.pushservice.web.config;

import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;

import java.util.HashMap;
import java.util.Map;

    @Configuration
    public class KafkaProducerConfig {

        @Value("${spring.kafka.bootstrap-servers}")
        private String bootstrapServers;

        @Bean
        public Map<String, Object> producerConfigs() {
            Map<String, Object> props = new HashMap<>();
            props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
            props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
            props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
            return props;
        }

        @Bean
        public ProducerFactory<String, String> producerFactory() {
            return new DefaultKafkaProducerFactory<>(producerConfigs());
        }

        @Bean
        public KafkaTemplate<String, String> kafkaTemplate() {
            return new KafkaTemplate<>(producerFactory());
        }

    }

第四步：写测试接口

package com.qcby.pushservice.web.controller;

import com.baomidou.mybatisplus.extension.api.R;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
@RestController
public class KafkaTestController {

    @Resource
    private KafkaTemplate<String, String> kafkaTemplate;

    @GetMapping("/test")
    public String testKafka() {
        String message = "hello";
        kafkaTemplate.send("test", message);
        return message;
    }
}

第五步：创建消费者配置

package com.qcby.pushservice.web.config;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;

import java.util.HashMap;
import java.util.Map;

@Configuration
@EnableKafka
public class KafkaConsumerConfig {
    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;

    @Value("${spring.kafka.consumer.group-id}")
    private String groupId;

    @Bean
    public Map<String, Object> consumerConfigs() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        return props;
    }

    @Bean
    public ConsumerFactory<String, String> consumerFactory() {
        return new DefaultKafkaConsumerFactory<>(consumerConfigs());
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());
        return factory;
    }

}

第六步：创建一个真实的消费者测试

package com.qcby.pushservice.web.mq;

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

/**
 * 卡夫卡消费者
 *
 * @author 王凯欣
 * @date 2023/05/21
 */
@Service
public class KafkaConsumer {
    @KafkaListener(topics = "test", groupId = "pushservice-system-web")
    public void consume(String message) {
        System.out.println("Received message: " + message);
    }
}

最后一步，打开浏览器测试

ok，测试成功！