kafka-消费者服务搭建&配置&简单消费（SpringBoot整合Kafka）

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

2、创建生产者发送消息

[root@localhost ~]# kafka-console-producer.sh --bootstrap-server 192.168.74.148:9095,192.168.748:9096,192.168.74.148:9097 --topic my_topic1
>1
>2
>3
>

[
  [
    {
      "partition": 1,
      "offset": 0,
      "msg": "1",
      "timespan": 1717592203289,
      "date": "2024-06-05 12:56:43"
    },
    {
      "partition": 1,
      "offset": 1,
      "msg": "2",
      "timespan": 1717592204046,
      "date": "2024-06-05 12:56:44"
    },
    {
      "partition": 1,
      "offset": 2,
      "msg": "3",
      "timespan": 1717592204473,
      "date": "2024-06-05 12:56:44"
    }
  ]
]

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

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 onMessage(ConsumerRecord<String, String> record) {
        System.out.println("消费者获取到消息：topic = "+ record.topic()
                +"，partition:"+record.partition()
                +"，offset = "+record.offset()
                +"，key = "+record.key()
                +"，value = "+record.value());
    }

}

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);
    }

}

6、屏蔽 kafka debug 日志 logback.xml

<configuration>　　　　　　
    <!-- 如果觉得idea控制台日志太多，src\main\resources目录下新建logback.xml
屏蔽kafka debug -->
    <logger name="org.apache.kafka.clients" level="debug" />
</configuration>

7、引入spring-kafka依赖

<?xml version="1.0" encoding="UTF-8"?>
<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>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <!-- 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 -->
    <groupId>com.atguigu</groupId>
    <artifactId>spring-kafka-consumer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-kafka-consumer</name>
    <description>spring-kafka-consumer</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

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

    </dependencies>

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

</project>

此时启动SpringKafkaConsumerApplication，控制台会打印数据

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

消费者获取到消息：topic = my_topic1，partition:1，offset = 0，key = null，value = 1
消费者获取到消息：topic = my_topic1，partition:1，offset = 1，key = null，value = 2
消费者获取到消息：topic = my_topic1，partition:1，offset = 2，key = null，value = 3

如果此时重新启动SpringKafkaConsumerApplication，控制台将不会打印数据，因为已经消费过数据

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