【引言】
kafka近几年更新非常快，也可以看出kafka在企业中是用的频率越来越高，在springboot中集成kafka还是比较简单的，但是应该注意使用的版本和kafka中基本配置，这个地方需要信心，防止进入坑中。
版本对应地址：https://spring.io/projects/spring-kafka
【基本环境】
springboot版本2.1.4
kafka版本2.2.0
jdk 1.8
【代码编写】
1、基本引用pom
<?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> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.4.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <name>kafkademo</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.kafka</groupId> <artifactId>spring-kafka</artifactId> <version>2.2.0.RELEASE</version> </dependency> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.7</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
2、基本配置
spring.kafka.bootstrap-servers=2.1.1.1:9092 spring.kafka.consumer.group-id=test-consumer-group spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer #logging.level.root=debug
3、实体类
package com.example.demo.model; import java.util.Date; public class Messages { private Long id; private String msg; private Date sendTime; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } public Date getSendTime() { return sendTime; } public void setSendTime(Date sendTime) { this.sendTime = sendTime; } }
4、生产者端
package com.example.demo.service; import com.example.demo.model.Messages; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.kafka.core.KafkaTemplate; import org.springframework.kafka.support.SendResult; import org.springframework.stereotype.Service; import org.springframework.util.concurrent.ListenableFuture; import java.util.Date; import java.util.UUID; @Service public class KafkaSender { @Autowired private KafkaTemplate<String, String> kafkaTemplate; private Gson gson = new GsonBuilder().create(); public void send() { Messages message = new Messages(); message.setId(System.currentTimeMillis()); message.setMsg("123"); message.setSendTime(new Date()); ListenableFuture<SendResult<String, String>> test0 = kafkaTemplate.send("newtopic", gson.toJson(message)); } }
5、消费者
package com.example.demo.service; import org.apache.kafka.clients.consumer.ConsumerRecord; import org.springframework.kafka.annotation.KafkaListener; import org.springframework.stereotype.Service; import java.util.Optional; @Service public class KafkaReceiver { @KafkaListener(topics = {"newtopic"}) public void listen(ConsumerRecord<?, ?> record) { Optional<?> kafkaMessage = Optional.ofNullable(record.value()); if (kafkaMessage.isPresent()) { Object message = kafkaMessage.get(); System.out.println("record =" + record); System.out.println("message =" + message); } } }
6、测试
在启动方法中模拟消息生产者，向kafka中发送消息
package com.example.demo; import com.example.demo.service.KafkaSender; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.ConfigurableApplicationContext; @SpringBootApplication public class KafkademoApplication { public static void main(String[] args) { ConfigurableApplicationContext context = SpringApplication.run(KafkademoApplication.class, args); KafkaSender sender = context.getBean(KafkaSender.class); for (int i = 0; i <1000; i++) { sender.send(); try { Thread.sleep(300); } catch (InterruptedException e) { e.printStackTrace(); } } } }
7、效果
命令行直接消费消息
8、遇到的问题
生产端连接kafka超时
at org.apache.kafka.common.network.NetworkReceive.readFrom(NetworkReceive.java:119)
解决方案：
修改kafka中的server.properties中的下面配置，将原来的默认配置替换成下面ip+端口的形式，重启kafka
