SpringBoot系列（四）使用spring-kafka实现生产者消费者demo代码

一、引入spring-kafka的maven依赖

<dependency>

	<groupId>org.springframework.kafka</groupId>

	<artifactId>spring-kafka</artifactId>

	<version>2.5.4.RELEASE</version>

</dependency>

方式一、创建springboot-web项目，自动引入（本文以此为例创建）

打开IDEA-File-New-Project，选择Spring Initializr初始化方式，Next，Next
选中Web中的Spring Web依赖，点击添加
选中Messaging中的Spring for Apache Kafka依赖，点击添加
创建项目

方式二、创建maven项目，手动引入

打开IDEA-File-New-Project，选择Maven初始化方式
添加如下依赖到pom.xml文件
经过创建启动类，构造Web环境后，剩余操作跟方式一类似。

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.5.5</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.kafka</groupId>

            <artifactId>spring-kafka</artifactId>

        </dependency>

    </dependencies>

二、生产者demo代码

step1：application.properties配置文件中，只开producer的配置，将consumer的配置注释

server.port=8080

#kafka

spring.kafka.bootstrap-servers=0.0.0.0:9092

#kafka producer

spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer

spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer

spring.kafka.producer.acks=all

spring.kafka.producer.retries=0

#kafka consumer

#spring.kafka.consumer.group-id=group_id

#spring.kafka.consumer.enable-auto-commit=true

#spring.kafka.consumer.auto-commit-interval=5000

#spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer

#spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer

step2：spring会自动加载这些配置，初始化生产者，其使用方式如下：

直接调用方式

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.kafka.core.KafkaTemplate;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

/**

 * kafka 生产者样例代码

 * @author cavan

 */

@RestController

@RequestMapping("/kafka")

public class KafkaController {

    private static final Logger LOGGER = LoggerFactory.getLogger(KafkaController.class);

    private static final String TOPIC = "topic-test";

    @Autowired

    private KafkaTemplate<String, String> kafkaTemplate;

    @PostMapping(value = "/publish")

    public String sendMessageTokafkaTopic(@RequestParam("message")  String message) {

        LOGGER.info(String.format("------ Producing message ------ %s", message));

        kafkaTemplate.send(TOPIC, message);

        return "ok";

    }

}

封装后调用

封装代码

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.kafka.core.KafkaTemplate;

import org.springframework.stereotype.Service;

/**

 * kafka producer

 *

 * @author cavan

 */

@Service

public class Producer {

    private static final Logger LOGGER = LoggerFactory.getLogger(Producer.class);

    @Autowired

    private KafkaTemplate<String, String> kafkaTemplate;

    public void sendMessage(String topic, String message) {

        LOGGER.info(String.format("Producing message is: %s", message));

        kafkaTemplate.send(topic, message);

    }

}

调用代码

import com.example.demo.kafka.Producer;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.kafka.core.KafkaTemplate;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

/**

 * kafka send message

 *

 * @author cavan

 */

@RestController

@RequestMapping("/kafka")

public class KafkaController {

    private static final Logger LOGGER = LoggerFactory.getLogger(KafkaController.class);

    private static final String TOPIC = "topic-test";

    @Autowired

    private Producer producer;

    @PostMapping(value = "/producer")

    public String sendMessageTokafka(@RequestParam("message")  String message) {

        LOGGER.info(String.format("------ Producing message ------ %s", message));

        producer.sendMessage(TOPIC, message);

        return "ok";

    }

}

postman调用接口测试

生产者日志：

2021-10-08 19:26:50.205 INFO 20836 --- [nio-8080-exec-2] c.e.demo.controller.KafkaController : ------ Producing message ------ success

三、消费者demo代码

step1：application.properties配置文件中，增加consumer的配置

server.port=8080

#kafka

spring.kafka.bootstrap-servers=0.0.0.0:9092

#kafka producer

spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer

spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer

spring.kafka.producer.acks=all

spring.kafka.producer.retries=0

#kafka consumer

spring.kafka.consumer.group-id=group_id

spring.kafka.consumer.enable-auto-commit=true

spring.kafka.consumer.auto-commit-interval=5000

spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer

spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer

step2：spring会自动加载这些配置，初始化消费者，其使用方式如下：

import org.apache.kafka.clients.consumer.ConsumerRecord;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.kafka.annotation.KafkaListener;

import org.springframework.stereotype.Service;

/**

 * kafka consumer demo

 *

 * @author cavan

 */

@Service

public class Consumer {

    private static final Logger LOGGER = LoggerFactory.getLogger(Consumer.class);

    @KafkaListener(id = "test", topics = "topic-test")

    public void listen(ConsumerRecord<?, ?> record) {

        LOGGER.info(

                "topic ={},partition={},offset={},customer={},value={}",

                record.topic(),

                record.partition(),

                record.offset(),

                record.key(),

                record.value());

    }

}

消费成功日志：

2021-10-08 19:55:23.004 INFO 11340 --- [nio-8080-exec-2] o.a.kafka.common.utils.AppInfoParser : Kafka version: 2.7.1
2021-10-08 19:55:23.004 INFO 11340 --- [nio-8080-exec-2] o.a.kafka.common.utils.AppInfoParser : Kafka commitId: 61dbce85d0d41457
2021-10-08 19:55:23.004 INFO 11340 --- [nio-8080-exec-2] o.a.kafka.common.utils.AppInfoParser : Kafka startTimeMs: 1633694123004
2021-10-08 19:55:23.117 INFO 11340 --- [ad | producer-1] org.apache.kafka.clients.Metadata : [Producer clientId=producer-1] Cluster ID: Lx7DFjG5SYuOLlJKtz2NCQ
2021-10-08 19:55:23.236 INFO 11340 --- [ test-0-C-1] com.example.demo.kafka.Consumer : topic =topic-test,partition=0,offset=31,customer=null,value=success