kafka-消费者组（SpringBoot整合Kafka）

1、消费者组

1.1、使用 efak 创建 主题 my_topic1 并建立6个分区并给每个分区建立3个副本

1.2、创建生产者发送消息

package com.atguigu.spring.kafka.consumer;

import jakarta.annotation.Resource;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.kafka.core.KafkaTemplate;

@SpringBootTest
class SpringKafkaConsumerApplicationTests {
    @Resource
    KafkaTemplate kafkaTemplate;

    @Test
    void contextLoads() {
        for (int i = 0; i < 10; i++) {
            kafkaTemplate.send("my_topic1",i%6,"", "消费者组"+i);
        }
    }
}

1.3、application.yml配置

server:
  port: 8120

# v1
spring:
  Kafka:
    bootstrap-servers: 192.168.74.148:9095,192.168.74.148:9096,192.168.74.148:9097
    consumer:
      # read-committed读事务已提交的消息 解决脏读问题
      isolation-level: read-committed # 消费者的事务隔离级别：read-uncommitted会导致脏读，可以读取生产者事务还未提交的消息
      # 消费者是否自动ack ：true自动ack 消费者获取到消息后kafka提交消费者偏移量
      enable-auto-commit: true 
      # 消费者提交ack时多长时间批量提交一次
      auto-commit-interval: 1000
      # 消费者第一次消费主题消息时从哪个位置开始
      auto-offset-reset: earliest  #指定Offset消费:earliest | latest | none
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

1.4、创建消费者监听器

package com.atguigu.spring.kafka.consumer.listener;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;
@Component
public class MyKafkaListener {

    @KafkaListener(topics ={"my_topic1"},groupId = "my_group1")
    public void onMessage1(ConsumerRecord<String, String> record) {
        System.out.println("my_group1消费者1获取到消息：topic = "+ record.topic()
                +"，partition:"+record.partition()
                +"，offset = "+record.offset()
                +"，key = "+record.key()
                +"，value = "+record.value());
    }
    @KafkaListener(topics ={"my_topic1"},groupId = "my_group1")
    public void onMessage2(ConsumerRecord<String, String> record) {
        System.out.println("my_group1消费者2获取到消息：topic = "+ record.topic()
                +"，partition:"+record.partition()
                +"，offset = "+record.offset()
                +"，key = "+record.key()
                +"，value = "+record.value());
    }
    @KafkaListener(topics ={"my_topic1"},groupId = "my_group2")
    public void onMessage3(ConsumerRecord<String, String> record) {
        System.out.println("my_group2消费者获取到消息：topic = "+ record.topic()
                +"，partition:"+record.partition()
                +"，offset = "+record.offset()
                +"，key = "+record.key()
                +"，value = "+record.value());
    }

}

1.5、创建SpringBoot启动类

package com.atguigu.spring.kafka.consumer;

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


// Generated by https://start.springboot.io
// 优质的 spring/boot/data/security/cloud 框架中文文档尽在 => https://springdoc.cn
@SpringBootApplication
public class SpringKafkaConsumerApplication {

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

}

1.6、屏蔽 kafka debug 日志 logback.xml

<configuration>　　　　　　
    
    <logger name="org.apache.kafka.clients" level="debug" />
configuration>

1.7、引入spring-kafka依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>3.0.5version>
        <relativePath/> 
    parent>

    
    
    <groupId>com.atguigugroupId>
    <artifactId>spring-kafka-consumerartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>spring-kafka-consumername>
    <description>spring-kafka-consumerdescription>
    <properties>
        <java.version>17java.version>
    properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starterartifactId>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.kafkagroupId>
            <artifactId>spring-kafkaartifactId>
        dependency>

    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
            plugin>
        plugins>
    build>

project>

1.8、消费者控制台：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v3.0.5)

my_group2消费者获取到消息：topic = my_topic1，partition:2，offset = 0，key = ，value = 消费者组2
my_group2消费者获取到消息：topic = my_topic1，partition:2，offset = 1，key = ，value = 消费者组8
my_group2消费者获取到消息：topic = my_topic1，partition:0，offset = 0，key = ，value = 消费者组0
my_group2消费者获取到消息：topic = my_topic1，partition:0，offset = 1，key = ，value = 消费者组6
my_group2消费者获取到消息：topic = my_topic1，partition:5，offset = 0，key = ，value = 消费者组5
my_group2消费者获取到消息：topic = my_topic1，partition:3，offset = 0，key = ，value = 消费者组3
my_group2消费者获取到消息：topic = my_topic1，partition:3，offset = 1，key = ，value = 消费者组9
my_group2消费者获取到消息：topic = my_topic1，partition:1，offset = 0，key = ，value = 消费者组1
my_group2消费者获取到消息：topic = my_topic1，partition:1，offset = 1，key = ，value = 消费者组7
my_group2消费者获取到消息：topic = my_topic1，partition:4，offset = 0，key = ，value = 消费者组4
my_group1消费者2获取到消息：topic = my_topic1，partition:2，offset = 0，key = ，value = 消费者组2
my_group1消费者2获取到消息：topic = my_topic1，partition:2，offset = 1，key = ，value = 消费者组8
my_group1消费者1获取到消息：topic = my_topic1，partition:5，offset = 0，key = ，value = 消费者组5
my_group1消费者1获取到消息：topic = my_topic1，partition:4，offset = 0，key = ，value = 消费者组4
my_group1消费者1获取到消息：topic = my_topic1，partition:3，offset = 0，key = ，value = 消费者组3
my_group1消费者1获取到消息：topic = my_topic1，partition:3，offset = 1，key = ，value = 消费者组9
my_group1消费者2获取到消息：topic = my_topic1，partition:1，offset = 0，key = ，value = 消费者组1
my_group1消费者2获取到消息：topic = my_topic1，partition:1，offset = 1，key = ，value = 消费者组7
my_group1消费者2获取到消息：topic = my_topic1，partition:0，offset = 0，key = ，value = 消费者组0
my_group1消费者2获取到消息：topic = my_topic1，partition:0，offset = 1，key = ，value = 消费者组6