Kafka简单Demo
首先，在虚拟机上搭建一个Kafka，可以参考这里：Linux 安装Kafka单机、集群。
新建一个spring boot工程，引入maven依赖：kafka-client，如下：
org.apache.kafka
kafka-clients
2.0.0
接着实现生产者发送消息，如下：
package org.example.kafka;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;
import java.util.Properties;
/**
* 实现生产者
*/
public class OriginalProducer implements Runnable {
private static final String TOPIC = "TEST_TOPIC";
private static final String BROKER_LIST = "192.168.3.4:9092,192.168.3.5:9092,192.168.3.6:9092";
/**
* 消息发送确认
* 0，只要消息提交到消息缓冲，就视为消息发送成功
* 1，只要消息发送到分区Leader且写入磁盘，就视为消息发送成功
* all，消息发送到分区Leader且写入磁盘，同时其他副本分区也同步到磁盘，才视为消息发送成功
*/
private static final String ACKS_CONFIG = "all";
/**
* 缓存消息数达到此数值后批量提交
*/
private static final String BATCH_SIZE_CONFIG = "1";
private static KafkaProducer producer;
static {
Properties properties = new Properties();
properties.setProperty(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, BROKER_LIST);
properties.setProperty(ProducerConfig.ACKS_CONFIG, ACKS_CONFIG);
properties.setProperty(ProducerConfig.BATCH_SIZE_CONFIG, BATCH_SIZE_CONFIG);
properties.setProperty(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
properties.setProperty(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
producer = new KafkaProducer(properties);
}
@Override
public void run() {
try {
// 等待启动日志打印完后再发送消息
Thread.sleep(10000L);
String message = "This is a message ";
for (int i = 0; i < 2; i++) {
ProducerRecord record = new ProducerRecord<>(TOPIC, message + i);
producer.send(record, (recordMetadata, e) -> {
if (e != null) {
System.out.println("发送消息异常！");
}
if (recordMetadata != null) {
// topic 下可以有多个分区，每个分区的消费者维护一个 offset
System.out.println("消息发送成功：" + recordMetadata.partition() + "-" + recordMetadata.offset());
}
});
Thread.sleep(1000L);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
producer.close();
}
}
}
然后实现消费者消费消息，如下：
package org.example.kafka;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;
import java.time.Duration;
import java.util.Arrays;
import java.util.Properties;
/**
* 官方jar实现消费者
*/
public class OriginalConsumer implements Runnable {
/**
* 服务器列表，多个用 , 隔开
*/
private static final String BROKER_LIST = "192.168.3.4:9092,192.168.3.5:9092,192.168.3.6:9092";
/**
* 客户端收到消息后，在处理消息前自动提交（即消息已消费），增加偏移量
*/
private static final String ENABLE_AUTO_COMMIT_CONFIG = "true";
/**
* 自动提交的频率，1S
*/
private static final String AUTO_COMMIT_INTERVAL_MS_CONFIG = "1000";
/**
* 一个主题下可以有多个分区、可以有多个消费者组消费消息
* 一个分区对应一个消费者（如分区P对应消费者C，则同个消费者组下的其他消费者不能再消费此分区的消息，只能消费其他分区的消息）
* 若有多个消费者组，则一个分区可以分配给不同消费者组下的消费者进行消费（各自维护一个offSet）
* 一个消费者组下可以有多个消费者
* 一个消费者可以消费一个或多个分区的消息
* 同一个消费组下，消费者数应小于等于分区数
*
* 正常消息队列（消息只消费一次）
* 可以设置一个主题，一个消费者组，消费者组下多个消费者
*
* 发布订阅（广播模式）
* 可以设置一个主题，多个消费者组，每个消费者组下一个或多个消费者
*/
/**
* 因为有多个消费者，所以先用命令创建好多分区的主题
*/
private static final String TOPIC = "TEST_TOPIC";
/**
* 消费者组：A
*/
public static final String GROUP_ID_A = "TEST_GROUP_A";
/**
* 消费者组：B
*/
public static final String GROUP_ID_B = "TEST_GROUP_B";
/**
* 消费者：A
*/
public static final String CLIENT_ID_A = "TEST_CLIENT_A";
/**
* 消费者：B
*/
public static final String CLIENT_ID_B = "TEST_CLIENT_B";
/**
* 消费者：C
*/
public static final String CLIENT_ID_C = "TEST_CLIENT_C";
private KafkaConsumer consumer;
private String clientId;
public OriginalConsumer(String groupId, String clientId) {
this.clientId = clientId;
Properties properties = new Properties();
properties.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, BROKER_LIST);
properties.setProperty(ConsumerConfig.GROUP_ID_CONFIG, groupId);
properties.setProperty(ConsumerConfig.CLIENT_ID_CONFIG, clientId);
properties.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, ENABLE_AUTO_COMMIT_CONFIG);
properties.setProperty(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, AUTO_COMMIT_INTERVAL_MS_CONFIG);
properties.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
properties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
consumer = new KafkaConsumer(properties);
consumer.subscribe(Arrays.asList(TOPIC));
}
private void consume() {
// 获取消息，超时时间：1S
ConsumerRecords records = consumer.poll(Duration.ofSeconds(1L));
records.forEach(record -> {
System.out.println(clientId + "-消费消息：" + record.toString());
});
}
@Override
public void run() {
try {
while (true) {
consume();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
consumer.close();
}
}
}
最后调用生产者发送消息、消费者消费消息，如下：
package org.example.kafka;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;
@Component
public class KafkaRunner implements ApplicationRunner {
@Autowired
private SpringKafkaProducer producer;
@Override
public void run(ApplicationArguments args) throws Exception {
// 启动生产者，发送两条消息
new Thread(new OriginalProducer()).start();
// A、B都在消费者组A下，故消息要么被A消费，要么被B消费
// 启动消费者A
new Thread(new OriginalConsumer(OriginalConsumer.GROUP_ID_A, OriginalConsumer.CLIENT_ID_A)).start();
// 启动消费者B
new Thread(new OriginalConsumer(OriginalConsumer.GROUP_ID_A, OriginalConsumer.CLIENT_ID_B)).start();
// 启动消费者C，在消费者组B下，可以消费到两条消息
new Thread(new OriginalConsumer(OriginalConsumer.GROUP_ID_B, OriginalConsumer.CLIENT_ID_C)).start();
}
}
运行结果，生产者发送了两条消息，C消费两条，A、B各消费一条，如下：
消息发送成功：0-21
消息发送成功：1-23
TEST_CLIENT_C-消费消息：ConsumerRecord(topic = TEST_TOPIC, partition = 0, offset = 21, CreateTime = 1615098562063, serialized key size = -1, serialized value size = 19, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = This is a message 0)
TEST_CLIENT_A-消费消息：ConsumerRecord(topic = TEST_TOPIC, partition = 0, offset = 21, CreateTime = 1615098562063, serialized key size = -1, serialized value size = 19, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = This is a message 0)
TEST_CLIENT_C-消费消息：ConsumerRecord(topic = TEST_TOPIC, partition = 1, offset = 23, CreateTime = 1615098563063, serialized key size = -1, serialized value size = 19, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = This is a message 1)
TEST_CLIENT_B-消费消息：ConsumerRecord(topic = TEST_TOPIC, partition = 1, offset = 23, CreateTime = 1615098563063, serialized key size = -1, serialized value size = 19, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = This is a message 1)下面使用spring-kafka来整合，引入maven依赖，如下：
org.springframework.kafka
spring-kafka
修改application.yml配置文件，增加kafka配置信息：
spring:
application:
name: demo
kafka:
bootstrap-servers: 192.168.3.4:9092,192.168.3.5:9092,192.168.3.6:9092
producer:
key-serializer: org.apache.kafka.common.serialization.StringSerializer
value-serializer: org.apache.kafka.common.serialization.StringSerializer
consumer:
group-id: TEST_GROUP
# 如果为true，则消费者的偏移量将在后台定期提交，为false，spring也会帮我们进行人工提交
enable-auto-commit: true
auto-commit-interval: 1000
key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
server:
port: 8080因为spring封装了一层，所以再实现生产者代码就简洁很多了，如下：
package org.example.kafka;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;
/**
* spring-kafka 生产者
*/
@Slf4j
@Component
public class SpringKafkaProducer {
@Autowired
private KafkaTemplate kafkaTemplate;
public void produce(String topic, String message) {
kafkaTemplate.send(topic, message);
log.info("生产者发送消息：{}，{}", topic, message);
}
public void produce(ProducerRecord record) {
kafkaTemplate.send(record);
log.info("生产者发送消息：{}", record.toString());
}
} 实现消费者，如下：
package org.example.kafka;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;
/**
* spring-kafka 消费者
*/
@Slf4j
@Component
public class SpringKafkaConsumer {
/**
* 因为有多个消费者，所以先用命令创建一个多分区的主题（防止出现消费者没有分区可以消费）
*/
public static final String SPRING_TEST_TOPIC = "SPRING_TEST_TOPIC";
public static final String SPRING_TEST_GROUP_A = "SPRING_TEST_GROUP_A";
public static final String SPRING_TEST_GROUP_A_CLIENT_A = "SPRING_TEST_GROUP_A_CLIENT_A";
public static final String SPRING_TEST_GROUP_A_CLIENT_B = "SPRING_TEST_GROUP_A_CLIENT_B";
public static final String SPRING_TEST_GROUP_B = "SPRING_TEST_GROUP_B";
public static final String SPRING_TEST_GROUP_B_CLIENT_C = "SPRING_TEST_GROUP_B_CLIENT_C";
/**
* 消费主题：SPRING_TEST_TOPIC
* 消费组：SPRING_TEST_GROUP_A
* 消费者：SPRING_TEST_GROUP_A_CLIENT_A
*
* 因为组 A 下有 CLIENT_A、CLIENT_B 两个消费者，故消息要么被 CLIENT_A 消费，要么被 CLIENT_B 消费
*/
@KafkaListener(topics = {SPRING_TEST_TOPIC}, groupId = SPRING_TEST_GROUP_A, id = SPRING_TEST_GROUP_A_CLIENT_A)
public void consumeA(ConsumerRecord record) {
log.info("消费者 A 消费消息：{}", record.toString());
}
/**
* 消费主题：SPRING_TEST_TOPIC
* 消费组：SPRING_TEST_GROUP_A
* 消费者：SPRING_TEST_GROUP_A_CLIENT_B
*
* 因为组 A 下有 CLIENT_A、CLIENT_B 两个消费者，故消息要么被 CLIENT_A 消费，要么被 CLIENT_B 消费
*/
@KafkaListener(topics = {SPRING_TEST_TOPIC}, groupId = SPRING_TEST_GROUP_A, id = SPRING_TEST_GROUP_A_CLIENT_B)
public void consumeB(ConsumerRecord record) {
log.info("消费者 B 消费消息：{}", record.toString());
}
/**
* 消费主题：SPRING_TEST_TOPIC
* 消费组：SPRING_TEST_GROUP_B
* 消费者：SPRING_TEST_GROUP_B_CLIENT_C
*
* 因为 GROUP_B 下只有 CLIENT_C 一个消费者，故 CLIENT_C 会消费所有发送到 SPRING_TEST_TOPIC 的消息
*/
@KafkaListener(topics = {SPRING_TEST_TOPIC}, groupId = SPRING_TEST_GROUP_B, id = SPRING_TEST_GROUP_B_CLIENT_C)
public void consumeC(ConsumerRecord record) {
log.info("消费者 C 消费消息：{}", record.toString());
}
}
修改KafkaRunner代码，启动时调用生产者发送消息，如下：
// spring-kafka
// 生产者发送消息
for (int i = 0; i < 10; i++) {
ProducerRecord record = new ProducerRecord<>(SpringKafkaConsumer.SPRING_TEST_TOPIC, String.valueOf(i));
producer.produce(record);
} 启动项目运行，可以看到生产者发送10条消息，然后消费者A、B一同消费这10条消息，另一个消费组的消费者C单独消费这10条消息，如下：
2021-03-07 14:29:12.113 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=0, timestamp=null)
2021-03-07 14:29:12.115 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=1, timestamp=null)
2021-03-07 14:29:12.118 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=2, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=3, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=4, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=5, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=6, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=7, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=8, timestamp=null)
2021-03-07 14:29:12.119 INFO 5740 --- [ main] org.example.kafka.SpringKafkaProducer : 生产者发送消息：ProducerRecord(topic=SPRING_TEST_TOPIC, partition=null, headers=RecordHeaders(headers = [], isReadOnly = true), key=null, value=9, timestamp=null)
2021-03-07 14:29:12.346 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 14, CreateTime = 1615098552118, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 2)
2021-03-07 14:29:12.346 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 5)
2021-03-07 14:29:12.346 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 16, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 8)
2021-03-07 14:29:12.351 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 14, CreateTime = 1615098552115, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 1)
2021-03-07 14:29:12.351 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 4)
2021-03-07 14:29:12.352 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 14, CreateTime = 1615098552118, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 2)
2021-03-07 14:29:12.352 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 16, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 7)
2021-03-07 14:29:12.352 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 5)
2021-03-07 14:29:12.352 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 0, offset = 16, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 8)
2021-03-07 14:29:12.354 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 14, CreateTime = 1615098552115, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 1)
2021-03-07 14:29:12.354 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 4)
2021-03-07 14:29:12.354 INFO 5740 --- [_CLIENT_A-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 A 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 1, offset = 16, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 7)
2021-03-07 14:29:12.410 INFO 5740 --- [_CLIENT_B-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 B 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 12, CreateTime = 1615098552102, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 0)
2021-03-07 14:29:12.410 INFO 5740 --- [_CLIENT_B-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 B 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 13, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 3)
2021-03-07 14:29:12.410 INFO 5740 --- [_CLIENT_B-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 B 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 14, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 6)
2021-03-07 14:29:12.410 INFO 5740 --- [_CLIENT_B-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 B 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 9)
2021-03-07 14:29:12.411 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 12, CreateTime = 1615098552102, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 0)
2021-03-07 14:29:12.411 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 13, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 3)
2021-03-07 14:29:12.411 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 14, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 6)
2021-03-07 14:29:12.411 INFO 5740 --- [_CLIENT_C-0-C-1] org.example.kafka.SpringKafkaConsumer : 消费者 C 消费消息：ConsumerRecord(topic = SPRING_TEST_TOPIC, partition = 2, offset = 15, CreateTime = 1615098552119, serialized key size = -1, serialized value size = 1, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = 9)
Demo~
https://github.com/191720653/demo