Kafka：Consumer订阅
Posted ITKaven
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Kafka：Consumer订阅相关的知识，希望对你有一定的参考价值。
测试代码
pom.xml：
<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.kaven</groupId>
<artifactId>kafka</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>3.0.0</version>
</dependency>
</dependencies>
</project>
创建Topic：
package com.kaven.kafka.admin;
import org.apache.kafka.clients.admin.*;
import org.apache.kafka.common.KafkaFuture;
import java.util.Collections;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
public class Admin
// 基于Kafka服务地址与请求超时时间来创建AdminClient实例
private static final AdminClient adminClient = Admin.getAdminClient(
"192.168.1.9:9092,192.168.1.9:9093,192.168.1.9:9094",
"40000");
public static void main(String[] args) throws InterruptedException, ExecutionException
Admin admin = new Admin();
// 创建Topic，Topic名称为topic1，分区数为1，复制因子为1
admin.createTopic("topic1", 1, (short) 1);
// 创建Topic，Topic名称为topic2，分区数为2，复制因子为1
admin.createTopic("topic2", 2, (short) 1);
// 创建Topic，Topic名称为topic3，分区数为2，复制因子为1
admin.createTopic("topic3", 2, (short) 1);
Thread.sleep(10000);
public static AdminClient getAdminClient(String address, String requestTimeoutMS)
Properties properties = new Properties();
properties.setProperty(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, address);
properties.setProperty(AdminClientConfig.REQUEST_TIMEOUT_MS_CONFIG, requestTimeoutMS);
return AdminClient.create(properties);
public void createTopic(String name, int numPartitions, short replicationFactor) throws InterruptedException
CountDownLatch latch = new CountDownLatch(1);
CreateTopicsResult topics = adminClient.createTopics(
Collections.singleton(new NewTopic(name, numPartitions, replicationFactor))
);
Map<String, KafkaFuture<Void>> values = topics.values();
values.forEach((name__, future) ->
future.whenComplete((a, throwable) ->
if(throwable != null)
System.out.println(throwable.getMessage());
System.out.println(name__);
latch.countDown();
);
);
latch.await();
Producer发布消息：
package com.kaven.kafka.producer;
import org.apache.kafka.clients.producer.*;
import java.util.Properties;
import java.util.concurrent.ExecutionException;
public class ProducerTest
public static void main(String[] args) throws ExecutionException, InterruptedException
send("topic1");
send("topic2");
send("topic3");
public static void send(String name) throws ExecutionException, InterruptedException
Producer<String, String> producer = ProducerTest.createProducer();
for (int i = 0; i < 7; i++)
ProducerRecord<String, String> producerRecord = new ProducerRecord<>(
name,
"key-" + i,
"value-" + i
);
// 异步发送并回调
producer.send(producerRecord, (metadata, exception) ->
if(exception == null)
System.out.printf("topic: %s, partition: %s, offset: %s\\n", name, metadata.partition(), metadata.offset());
else
exception.printStackTrace();
);
// 要关闭Producer实例
producer.close();
public static Producer<String, String> createProducer()
// Producer的配置
Properties properties = new Properties();
// 服务地址
properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.1.9:9092,192.168.1.9:9093,192.168.1.9:9094");
// KEY的序列化器类
properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
// VALUE的序列化器类
properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
return new KafkaProducer<>(properties);
Consumer可以订阅多个Topic或者多个Partition，先来演示订阅多个Topic：
package com.kaven.kafka.consumer;
import org.apache.kafka.clients.consumer.*;
import java.time.Duration;
import java.util.*;
public class ConsumerTest
public static void main(String[] args)
subscribeTopicList(Arrays.asList("topic1", "topic2", "topic3"));
public static void subscribeTopicList(List<String> topicList)
KafkaConsumer<String, String> consumer = createConsumer();
consumer.subscribe(topicList);
while (true)
ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(10000));
records.forEach((record) ->
System.out.printf("topic: %s, partition: %s, offset: %s, key: %s, value: %s\\n",
record.topic(), record.partition(), record.offset(), record.key(), record.value());
);
public static KafkaConsumer<String, String> createConsumer()
// Consumer的配置
Properties properties = new Properties();
// 服务地址
properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.1.9:9092,192.168.1.9:9093,192.168.1.9:9094");
// 组ID，用于标识此消费者所属的消费者组
properties.put(ConsumerConfig.GROUP_ID_CONFIG, "kaven-test");
// 开启offset自动提交
properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "true");
// 消费者offset自动提交到Kafka的频率（以毫秒为单位）
properties.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "1000");
// KEY的反序列化器类
properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
// VALUE的反序列化器类
properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
return new KafkaConsumer<>(properties);
通过下面这行代码即可订阅多个Topic：
consumer.subscribe(topicList);
先创建这几个Topic。
再启动Consumer订阅程序，现在还没有消息发布。
然后通过Producer发布消息到这几个Topic。
topic: topic1, partition: 0, offset: 21
topic: topic1, partition: 0, offset: 22
topic: topic1, partition: 0, offset: 23
topic: topic1, partition: 0, offset: 24
topic: topic1, partition: 0, offset: 25
topic: topic1, partition: 0, offset: 26
topic: topic1, partition: 0, offset: 27
topic: topic2, partition: 0, offset: 12
topic: topic2, partition: 0, offset: 13
topic: topic2, partition: 0, offset: 14
topic: topic2, partition: 0, offset: 15
topic: topic2, partition: 1, offset: 9
topic: topic2, partition: 1, offset: 10
topic: topic2, partition: 1, offset: 11
topic: topic3, partition: 0, offset: 12
topic: topic3, partition: 0, offset: 13
topic: topic3, partition: 0, offset: 14
topic: topic3, partition: 0, offset: 15
topic: topic3, partition: 1, offset: 9
topic: topic3, partition: 1, offset: 10
topic: topic3, partition: 1, offset: 11
此时Consumer就可以订阅到消息了，输出如下所示：
topic: topic1, partition: 0, offset: 21, key: key-0, value: value-0
topic: topic1, partition: 0, offset: 22, key: key-1, value: value-1
topic: topic1, partition: 0, offset: 23, key: key-2, value: value-2
topic: topic1, partition: 0, offset: 24, key: key-3, value: value-3
topic: topic1, partition: 0, offset: 25, key: key-4, value: value-4
topic: topic1, partition: 0, offset: 26, key: key-5, value: value-5
topic: topic1, partition: 0, offset: 27, key: key-6, value: value-6
topic: topic2, partition: 1, offset: 9, key: key-0, value: value-0
topic: topic2, partition: 1, offset: 10, key: key-3, value: value-3
topic: topic2, partition: 1, offset: 11, key: key-4, value: value-4
topic: topic2, partition: 0, offset: 12, key: key-1, value: value-1
topic: topic2, partition: 0, offset: 13, key: key-2, value: value-2
topic: topic2, partition: 0, offset: 14, key: key-5, value: value-5
topic: topic2, partition: 0, offset: 15, key: key-6, value: value-6
topic: topic3, partition: 0, offset: 12, key: key-1, value: value-1
topic: topic3, partition: 0, offset: 13, key: key-2, value: value-2
topic: topic3, partition: 0, offset: 14, key: key-5, value: value-5
topic: topic3, partition: 0, offset: 15, key: key-6, value: value-6
topic: topic3, partition: 1, offset: 9, key: key-0, value: value-0
topic: topic3, partition: 1, offset: 10, key: key-3, value: value-3
topic: topic3, partition: 1, offset: 11, key: key-4, value: value-4
输出是符合预期的，因为这不是第一次发布消息到这几个Topic上，博主之前测试过几次。再来演示Consumer订阅多个Partition：
package com.kaven.kafka.consumer;
import org.apache.kafka.clients.consumer.*;
import org.apache.kafka.common.TopicPartition;
import java.time.Duration;
import java.util.*;
public class ConsumerTest
public static void main(String[] args)
subscribeTopicPartitionList(ArraysKafka Java consumer动态修改topic订阅
Kafka获取订阅某topic的所有consumer group客户端版