springboot整合kafka(简单入门的例子)

jdk 1.8
springboot 2.1.6.RELEASE

1. 安装kafka和zookeeper
   我使用的是docker-compose部署，配置文件是从网上直接荡下来的，我也不知道具体配置什么意思，只知道zookeeper是2181端口，kafka是9092端口。

version: '2.3'
services:
  zoo1:
    image: wurstmeister/zookeeper
    restart: always
    hostname: zoo1
    ports:
      - "2181:2181"
    container_name: zookeeper

  # kafka version: 1.1.0
  # scala version: 2.12
  kafka1:
    image: wurstmeister/kafka
    restart: always
    ports:
      - "9092:9092"
    environment:
      KAFKA_ADVERTISED_HOST_NAME: localhost
      KAFKA_ZOOKEEPER_CONNECT: "zoo1:2181"
      KAFKA_BROKER_ID: 1
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_CREATE_TOPICS: "stream-in:1:1,stream-out:1:1"
    depends_on:
      - zoo1
    container_name: kafka

2. maven的POM文件

<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>4.0.0modelVersion>
   <parent>
       <groupId>org.springframework.bootgroupId>
       <artifactId>spring-boot-starter-parentartifactId>
       <version>2.1.6.RELEASEversion>
       <relativePath/> 
   parent>
   <groupId>com.ilovewlgroupId>
   <artifactId>kafka-demoartifactId>
   <version>1.0version>
   <name>kafka-demoname>
   <description>Kafka demo project for Spring Bootdescription>

   <properties>
       <java.version>1.8java.version>
   properties>
   <repositories>
       <repository>
           <id>aliyunid>
           <url>http://maven.aliyun.com/nexus/content/groups/publicurl>
           <name>aliyunname>
       repository>
   repositories>

   <dependencies>
       <dependency>
           <groupId>org.springframework.bootgroupId>
           <artifactId>spring-boot-starterartifactId>
       dependency>
       <dependency>
           <groupId>org.springframework.kafkagroupId>
           <artifactId>spring-kafkaartifactId>
           <version>2.2.7.RELEASEversion>
       dependency>
       <dependency>
           <groupId>org.springframework.bootgroupId>
           <artifactId>spring-boot-starter-testartifactId>
           <scope>testscope>
       dependency>
       <dependency>
           <groupId>org.projectlombokgroupId>
           <artifactId>lombokartifactId>
           <version>1.18.8version>
       dependency>
       <dependency>
           <groupId>com.google.code.gsongroupId>
           <artifactId>gsonartifactId>
           <version>2.8.2version>
       dependency>
       
       <dependency>
           <groupId>org.springframeworkgroupId>
           <artifactId>spring-txartifactId>
           <version>5.1.8.RELEASEversion>
       dependency>
   dependencies>

   <build>
       <plugins>
           <plugin>
               <groupId>org.springframework.bootgroupId>
               <artifactId>spring-boot-maven-pluginartifactId>
           plugin>
       plugins>
   build>

project>

3、重要的java文件
消息实体类

package com.ilovewl.kafkademo.model;

import java.util.Date;

import lombok.Data;

@Data
public class Message {
    private Long id;
    private String msg;
    private Date sendTime;

}

Kafka的消费者

package com.ilovewl.kafkademo.config;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.ilovewl.kafkademo.model.Message;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.UUID;

/**
 * @author: liuchangrong
 */
@Slf4j
@Component
public class KafkaSender {

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;
    private Gson gson = new GsonBuilder().create();

    /**
     *  发送消息方法
     */
    public void send() {
        Message message = new Message();
        message.setId(System.currentTimeMillis());
        message.setMsg(UUID.randomUUID().toString());
        message.setSendTime(new Date());
        log.info("消费者发送消息  message = {}", gson.toJson(message));
        //发送消息的主题为test
        kafkaTemplate.send("test", gson.toJson(message));
    }
}

Kafka的生产者

package com.ilovewl.kafkademo.config;

import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

import java.util.Optional;

/**
 * @author liuchangrong
 */
@Slf4j
@Component
public class KafkaReceiver {

    /**
     * 订阅主题为test的消息
     */
    @KafkaListener(topics = {"test"})
    public void listen(ConsumerRecord<?, ?> record) {
        Optional<?> kafkaMessage = Optional.ofNullable(record.value());
        if (kafkaMessage.isPresent()) {
            Object message = kafkaMessage.get();
            log.info("-----消费者收到消息-----");
            log.info("------------------ message =" + message);
        }
    }
}

5、配置application.properties

#============== kafka ===================
# 指定kafka 代理地址，可以多个
spring.kafka.bootstrap-servers=xxx.xxx.xxx.xxx:9092

#=============== provider  =======================

spring.kafka.producer.retries=0
# 每次批量发送消息的数量
spring.kafka.producer.batch-size=16384
spring.kafka.producer.buffer-memory=33554432

# 指定消息key和消息体的编解码方式
spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer

#=============== consumer  =======================
# 指定默认消费者group id
spring.kafka.consumer.group-id=test-consumer-group

spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.enable-auto-commit=true
spring.kafka.consumer.auto-commit-interval=100

# 指定消息key和消息体的编解码方式
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer

5、启动类

package com.ilovewl.kafkademo;

import com.ilovewl.kafkademo.config.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 < 3; i++) {
            //调用消息发送类中的消息发送方法
            sender.send();
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

}

启动之后会发现注册不上去kafka,然后我百度一波：
修改了配置文件advertiser.listeners=PLAINTEXT://hostname:9092

可以参考这篇博客：https://www.jianshu.com/p/71b295e1df4f

重启容器再重启程序发现程序正常运行。

---

参考了别人很多代码，在此表示感谢。

希望能帮到大家。