SpringBoot Kafka

实现一个SpringBoot应用程序，其中包含多个接收系统订阅多个发送系统，多个消费组和多个消费者。

1、添加依赖

在pom.xml文件中，添加kafka依赖

<dependency>  
    <groupId>org.springframework.kafka</groupId>  
    <artifactId>spring-kafka</artifactId>  
    <version>2.8.3</version>  
</dependency>

2、配置Kafka 

在application.properties或application.yml文件中，添加Kafka相关配置

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

3、创建Kafka生产者

创建一个Kafka生产者类，用于发送消息到Kafka： 

import org.springframework.kafka.core.KafkaTemplate;  
import org.springframework.stereotype.Service;  
  
@Service  
public class KafkaProducer {  
    private final KafkaTemplate<String, String> kafkaTemplate;  
  
    public KafkaProducer(KafkaTemplate<String, String> kafkaTemplate) {  
        this.kafkaTemplate = kafkaTemplate;  
    }  
  
    public void sendMessage(String topic, String message) {  
        kafkaTemplate.send(topic, message);  
    }  
}

4、创建Kafka消费者组1的消费者类

创建一个消费者类，用于消费Kafka中的消息：

import org.springframework.kafka.annotation.KafkaListener;  
import org.springframework.stereotype.Service;  
  
@Service  
public class KafkaConsumerGroup1 {  
    @KafkaListener(topics = "topic1", groupId = "my-consumer-group")  
    public void consumeMessage(String message) {  
        System.out.println("Consumer Group 1: " + message);  
    }  
}

5、创建Kafka消费者组2的消费者类

创建另一个消费者类，用于消费Kafka中的另一个主题的消息：

import org.springframework.kafka.annotation.KafkaListener;  
import org.springframework.stereotype.Service;  
  
@Service  
public class KafkaConsumerGroup2 {  
    @KafkaListener(topics = "topic2", groupId = "my-consumer-group")  
    public void consumeMessage(String message) {  
        System.out.println("Consumer Group 2: " + message);  
    }  
}