Spring Kafka和Spring Boot整合实现消息发送与消费简单案例

本文主要分享下Spring Boot和Spring Kafka如何配置整合，实现发送和接收来自Spring Kafka的消息。

先前我已经分享了Kafka的基本介绍与集群环境搭建方法。关于Kafka的介绍请阅读Apache Kafka简介与安装(一)，关于Kafka安装请阅读Apache Kafka安装，关于Kafka集群环境搭建请阅读Apache Kafka集群环境搭建 。这里关于服务器环境搭建不在赘述。

Spring Kafka整合Spring Boot创建生产者客户端案例

创建一个kafka-producer-master的maven工程。整个项目结构如下：

Maven的依赖

<?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.gzh.kafka.producer</groupId>
    <artifactId>producer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>kafka-producer-master</name>
    <description>demo project for kafka producer</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-kafka.version>2.1.5.RELEASE</spring-kafka.version>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.kafka/spring-kafka -->
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
            <version>${spring-kafka.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.kafka/spring-kafka-test -->
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka-test</artifactId>
            <version>${spring-kafka.version}</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger2 -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.8.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.8.0</version>
        </dependency>

    </dependencies>

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

</project>

使用application.properties配置应用程序

当然，根据个人喜好，你也可以使用application.yml属性文件重写配置。Spring Boot会尝试根据pom.xml文件中指定的依赖关系自动配置应用程序，并设置合理的默认值。

server.port=8000
spring.application.name=kafka-producer
#kafka configuration
spring.kafka.producer.bootstrap-servers=192.168.1.130:9092,192.168.1.101:9093,192.168.1.101:9094
spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer
#topic
kafka.app.topic.foo=test20180430

在上面的配置中，我给生产者分配的端口号是8000，服务器有3台，采用先前window环境搭建zookeeper,kafka集群 中配置的服务器。想了解关于kafka生产者相关的更多配置的话，可以阅读关于Spring Boot Kafka Properties的配置信息。

使用Spring Boot发送Spring Kafka消息

SpringKafka提供了使用Producer的KafkaTemplate类发送消息，并提供将数据发送到Kafka主题的高级操作。 提供异步和同步方法，异步方法返回Future。Spring Boot根据application.properties属性文件中配置的属性自动配置并初始化KafkaTemplate。为了方便测试发送消息，使用了Spring的定时任务，在类上使用@EnableScheduling 注解开启定时任务，通过@Scheduled注解指定发送消息规则。

package com.gzh.kafka.producer.component;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.SendResult;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import org.springframework.util.concurrent.ListenableFuture;

@Component
@EnableScheduling
public class KafkaMessageProducer {

    private static final Logger LOG = LoggerFactory.getLogger(KafkaMessageProducer.class);

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    @Value("${kafka.app.topic.foo}")
    private String topic;

    @Scheduled(cron = "00/5 * * * * ?")
    public void send() {
        String message = "Hello World---" + System.currentTimeMillis();
        LOG.info("topic="+topic+",message="+message);
        ListenableFuture<SendResult<String, String>> future = kafkaTemplate.send(topic, message);
        future.addCallback(success -> LOG.info("KafkaMessageProducer 发送消息成功！"),
                fail -> LOG.error("KafkaMessageProducer 发送消息失败！"));
    }
}

创建消息生产者启动类

package com.gzh.kafka.producer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties
public class KafkaProducerApplication{

    public static void main(String[] args) {
        SpringApplication.run(KafkaProducerApplication.class, args);
    }
}

至此，Spring Boot整合Spring Kafka消息生产者应用已经整合完毕。启动zookeeper、kafka各个服务器。启动生产者应用，查看消息生产者应用控制台日志，如下图说明整合OK。

当然在创建消息生产者类时，我们可以更加灵活，可以不使用定时任务，通过界面请求的方式，发送我们想要发送的内容。简单案例如下：

• 消息发送者类

package com.gzh.kafka.producer.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.SendResult;
import org.springframework.stereotype.Service;
import org.springframework.util.concurrent.ListenableFuture;

@Service
public class KafkaMessageSendService {

    private static final Logger LOG = LoggerFactory.getLogger(KafkaMessageSendService.class);

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    @Value("${kafka.app.topic.foo}")
    private String topic;

    public void send(String message){
        LOG.info("topic="+topic+",message="+message);
        ListenableFuture<SendResult<String, String>> future = kafkaTemplate.send(topic, message);
        future.addCallback(success -> LOG.info("KafkaMessageProducer 发送消息成功！"),
                fail -> LOG.error("KafkaMessageProducer 发送消息失败！"));
    }
}

• 界面请求处理controller类

package com.gzh.kafka.producer.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.gzh.kafka.producer.service.KafkaMessageSendService;

@RestController
@RequestMapping(value="send",produces=MediaType.APPLICATION_JSON_UTF8_VALUE)
public class KafkaMessageSendController {

    @Autowired
    private KafkaMessageSendService kafkaMessageSendService;

    @RequestMapping(value="/sendMessage",method=RequestMethod.POST)
    public String send(@RequestParam(required=true) String message){
        try {
            kafkaMessageSendService.send(message);
        } catch (Exception e) {
            return "send failed.";
        }
        return message;
    }
}

• 通过Swagger访问测试Controller服务请求

Spring Kafka整合Spring Boot创建消费者客户端案例：

创建一个kafka-consumer-master的maven工程。整个项目结构如下：

Maven的依赖

<?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.gzh.kafka.consumer</groupId>
    <artifactId>consumer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>kafka-consumer-master</name>
    <description>demo project for kafka consumer</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-kafka.version>1.3.4.RELEASE</spring-kafka.version>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.kafka/spring-kafka -->
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
            <version>${spring-kafka.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.kafka/spring-kafka-test -->
        <dependency>
            <groupId>org.springframework.kafka</groupId>
            <artifactId>spring-kafka-test</artifactId>
            <version>${spring-kafka.version}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

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

</project>

注意，这是使用Spring-Kafka时一定要注意版本问题，否则会报各种奇葩错误。Spring官方网站上给出了SpringKafka和kafka-client版本（它的版本号要和kafka服务器的版本保持一致）的对应关系：

使用application.properties配置应用程序

Spring Boot会尝试根据pom.xml文件中指定的依赖关系自动配置应用程序，并设置合理的默认值。

server.port=8001
spring.application.name=kafka-consumer

#kafka configuration
#指定消息被消费之后自动提交偏移量，以便下次继续消费
spring.kafka.consumer.enable-auto-commit=true
#指定消息组
spring.kafka.consumer.group-id=guan
#指定kafka服务器地址
spring.kafka.consumer.bootstrap-servers=192.168.1.130:9092,192.168.1.101:9093,192.168.1.101:9094
#指定从最近地方开始消费(earliest)
spring.kafka.consumer.auto-offset-reset=latest

spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer
#topic
kafka.app.topic.foo=test20180430

在上面的配置中，我给生产者分配的端口号是8000，服务器有3台，采用先前window环境搭建zookeeper,kafka集群 中配置的服务器。想了解关于kafka生产者相关的更多配置的话，可以阅读关于Spring Boot Kafka Properties的配置信息。

使用Spring Boot消费Spring Kafka消息

通过使用@KafkaListener来注解一个方法Spring Kafka会自动创建一个消息监听器容器。使用该注解，并指定要消费的topic（也可以指定消费组以及分区号，支持正则表达式匹配），这样，消费者一旦启动，就会监听kafka服务器上的topic，实时进行消费消息。

package com.gzh.kafka.consumer.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.handler.annotation.Headers;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.stereotype.Component;

@Component
public class KafkaMessageConsumer {

    private static final Logger LOG = LoggerFactory.getLogger(KafkaMessageConsumer.class);

    @KafkaListener(topics={"${kafka.app.topic.foo}"})
    public void receive(@Payload String message, @Headers MessageHeaders headers){
        LOG.info("KafkaMessageConsumer 接收到消息："+message);
        headers.keySet().forEach(key->LOG.info("{}: {}",key,headers.get(key)));
    }
}

创建消息消费者启动类

package com.gzh.kafka.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties
public class KafkaConsumerApplication {

    public static void main(String[] args) {
        SpringApplication.run(KafkaConsumerApplication.class, args);
    }
}

消费者应用已经完成，接下来让我们验证Spring Kafka消息发送和接收效果。先依次启动zookeeper、kafka服务器，然后在启动生产者(kafka-producer-master)应用，再启动消费者(kafka-consumer-master)应用，然后观察生产者和消费者启动类日志：