如何安装Kafka,可以参考docker搭载Kafka集群,一个文件搞定,超简单,亲试可行-CSDN博客
1、在pom.xml中加入依赖
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-stream-kafka</artifactId>
<version>3.1.6</version>
</dependency>
2、配置application.yml文件
在application.yml中加入
spring
kafka:
#Kafka地址,可以是一个,也可以是Kafka集群的地址,多个地址用逗号分隔
bootstrap-servers: 192.168.57.1xx:9093,192.168.57.1xx:9094,192.168.57.1xx:9095
producer:
# 消息确认模式:0=不等待确认,1=等待leader确认,all=所有副本确认
acks: 1
# 发送失败时的重试次数,0表示不重试
retries: 0
# 批量发送时的批次大小(字节)
batch-size: 30720000 # 30MB
# 生产者的内存缓冲区大小(字节)
buffer-memory: 33554432 # 32MB
# Key的序列化器类
key-serializer: org.apache.kafka.common.serialization.StringSerializer
# Value的序列化器类
value-serializer: org.apache.kafka.common.serialization.StringSerializer
consumer:
# 消费者所属的组ID
group-id: test-kafka
# 禁用自动提交offset,改为手动提交
enable-auto-commit: false
# 偏移量重置策略:
# earliest:从最早的记录开始消费
# latest:从最新的记录开始消费
auto-offset-reset: earliest
# Key的反序列化器类
key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
# Value的反序列化器类
value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
# 每次poll()调用返回的最大消息条数
max-poll-records: 2
session:
# 消费者会话超时时间,超时未发送心跳将被认为失联(毫秒)
timeout:
ms: 300000 # 5分钟
listener:
# 如果指定的主题不存在,是否让应用启动失败,false表示不会报错
missing-topics-fatal: false
# 消费模式:single=单条消息,batch=批量消费
type: single
# 消费确认模式:
# manual_immediate:手动确认消息,立即提交offset
ack-mode: manual_immediate
3、主要示例代码
创建一个目录和四个java文件,可以做测试
3.1、KafkaConfig.java
Kafka监听器配置
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
@EnableKafka
@Configuration
public class KafkaConfig {
// 单条消费监听器工厂,手动提交offset
@Bean
public ConcurrentKafkaListenerContainerFactory<String, String> singleFactory(
ConsumerFactory<String, String> consumerFactory) {
ConcurrentKafkaListenerContainerFactory<String, String> factory =
new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory);
factory.getContainerProperties().setAckMode(org.springframework.kafka.listener.ContainerProperties.AckMode.MANUAL_IMMEDIATE);
return factory;
}
// 批量消费监听器工厂,手动提交offset
@Bean
public ConcurrentKafkaListenerContainerFactory<String, String> batchFactory(
ConsumerFactory<String, String> consumerFactory) {
ConcurrentKafkaListenerContainerFactory<String, String> factory =
new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory);
factory.setBatchListener(true); // 启用批量消费
factory.getContainerProperties().setAckMode(org.springframework.kafka.listener.ContainerProperties.AckMode.MANUAL_IMMEDIATE);
return factory;
}
}
3.2、KafkaProducer.java
生产者
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.kafka.core.KafkaTemplate;
@SpringBootApplication
public class KafkaProducer {
public static void main(String[] args) {
SpringApplication.run(KafkaProducer.class, args);
}
@Bean
CommandLineRunner commandLineRunner(KafkaTemplate<String, String> kafkaTemplate) {
return args -> {
String topic = "test-topic";
for (int i = 1; i <= 10; i++) {
String message = "Message " + i;
kafkaTemplate.send(topic, message);
System.out.println("Sent: " + message);
Thread.sleep(500); // 模拟消息发送间隔
}
};
}
}
3.3、SingleConsumer.java
单条消息消费者
autoStartup参数:是是否自动启动;=”true“:自动启动,即生产者启动,该消费者将会开始消费;=”false":不自动启动,不开该模式的消费。
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.kafka.support.Acknowledgment;
import org.springframework.stereotype.Service;
@Service
public class SingleConsumer {
@KafkaListener(topics = "test-topic", groupId = "test-group", containerFactory = "singleFactory", autoStartup = "true")
public void listen(ConsumerRecord<String, String> record, Acknowledgment acknowledgment) {
System.out.println("SingleConsumer - Received: " + record.value());
// 手动提交offset
acknowledgment.acknowledge();
}
}
3.4、BatchConsumer.java
批量消息消费者
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.kafka.support.Acknowledgment;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class BatchConsumer {
@KafkaListener(topics = "test-topic", groupId = "test-group", containerFactory = "batchFactory", autoStartup = "false")
public void batchListen(List<String> messages, Acknowledgment acknowledgment) {
System.out.println("BatchConsumer - Received batch: " + messages);
// 手动提交offset
acknowledgment.acknowledge();
}
}
4、测试
4.1、单条信息消费模式
在SingleConsumer.java中设置autoStartup = "true",启动KafkaProducer.java
消费成功
4.2、批量信息消费模式
在BatchConsumer.java中设置autoStartup = "true",启动KafkaProducer.java
配置文件中设置了max-poll-records: 2,所有一次只消费两条
消费成功
如果在BatchConsumer.java和SingleConsumer.java中设置autoStartup = "true",Kafka会随机选择消费者组里的一个消费者进行消费,所有可以会导致其中一个消费者没有消费信息