kafka-消费者-指定offset消费（SpringBoot整合Kafka）_kafka指定offset消费

1、指定offset消费

1.1、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.kafka.annotation.PartitionOffset;
import org.springframework.kafka.annotation.TopicPartition;
import org.springframework.stereotype.Component;
@Component
public class MyKafkaPartitionListener {

    //初始化偏移量指定后，每次重启都会从该位置消费一轮，所以一般是调式解决问题时才使用
    @KafkaListener(
            topicPartitions = {
                    @TopicPartition(topic = "my_topic1"
                    ,partitionOffsets = {
                            @PartitionOffset(partition = "0",initialOffset = "2")
                    })}
            , 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());
    }

}

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1.2、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


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1.3、使用 Java代码 创建 主题 my_topic1 并建立3个分区并给每个分区建立3个副本

package com.atguigu.spring.kafka.consumer.config;
import org.apache.kafka.clients.admin.NewTopic;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.config.TopicBuilder;
@Configuration
public class MyKafkaConfig {
    @Bean
    public NewTopic springTestPartitionTopic() {
        return TopicBuilder.name("my_topic1") //主题名称
                .partitions(3) //分区数量
                .replicas(3) //副本数量
                .build();
    }
}


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1.4、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%3,"", "指定分区消费"+i);
        }
    }

}


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1.4.1、分区0中的数据

[
  [
    {
      "partition": 0,
      "offset": 0,
      "msg": "指定offset消费0",
      "timespan": 1717660785962,
      "date": "2024-06-06 07:59:45"
    },
    {
      "partition": 0,
      "offset": 1,
      "msg": "指定offset消费3",
      "timespan": 1717660785974,
      "date": "2024-06-06 07:59:45"
    },
    {
      "partition": 0,
      "offset": 2,
      "msg": "指定offset消费6",
      "timespan": 1717660785975,
      "date": "2024-06-06 07:59:45"
    },
    {
      "partition": 0,
      "offset": 3,
      "msg": "指定offset消费9",
      "timespan": 1717660785975,
      "date": "2024-06-06 07:59:45"
    }
  ]
]
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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);
    }

}


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1.6、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>

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1.7、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>

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1.8、消费者控制台：

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

my_group1消费者1获取到消息：topic = my_topic1，partition:0，offset = 2，key = ，value = 指定offset消费6
my_group1消费者1获取到消息：topic = my_topic1，partition:0，offset = 3，key = ，value = 指定offset消费9
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此时如果重新启动 SpringKafkaConsumerApplication 消费者还是会消费数据，重复消费

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

my_group1消费者1获取到消息：topic = my_topic1，partition:0，offset = 2，key = ，value = 指定offset消费6
my_group1消费者1获取到消息：topic = my_topic1，partition:0，offset = 3，key = ，value = 指定offset消费9
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