Kafka集成springboot

安装kafka，直接到官网下载bin文件，本文使用windows进行使用kafka。

下载之后，第一步，启动zookeeper：

zookeeper-server-start.bat ....\config\zookeeper.properties

第二步，启动kafka：

kafka-server-start.bat ....\config\server.properties

第三步，在pom中导入依赖：

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- kafkfa -->
    <dependency>
        <groupId>org.springframework.kafka</groupId>
        <artifactId>spring-kafka</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.apache.kafka</groupId>
                <artifactId>kafka-clients</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
    </dependency>

第四步，修改yml文件，添加配置：

spring:
  kafka:
    bootstrap-servers: localhost:9092
    producer:
      retries: 10
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer
    consumer:
      group-id: ${spring.application.name}-test
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

第五步， 即可编写测试类（测试消息队列）：

生产者：

package com.farm.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @Autowired
    private KafkaTemplate<String,String> kafkaTemplate;

    @GetMapping("/hello")
    public String hello(){
        kafkaTemplate.send("topic1","你好旧时光");
        return "ok";
    }
}

消费者：

package com.farm.controller;

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

@Component
public class HelloListener {

    @KafkaListener(topics = "topic1")
    public void onMessage(String message){
        if(!StringUtils.isEmpty(message)){
            System.out.println(message);
        }

    }
}

效果如下：

只要访问/hello就可以触发生产者向topic1主题发送“你好旧时光”的字样，通过注解可以让消费者消费这条消息。

补充：发送对象，采用fastjson进行封装：

@GetMapping("/hello")
public String hello(){
    User user = new User();
    user.setUsername("xiaowang");
    user.setAge(18);

    kafkaTemplate.send("topic1", JSON.toJSONString(user));

    return "ok";
}

消费者：

package com.heima.kafka.listener;

import com.alibaba.fastjson.JSON;
import com.heima.kafka.pojo.User;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

@Component
public class HelloListener {

    @KafkaListener(topics = "topic1")
    public void onMessage(String message){
        if(!StringUtils.isEmpty(message)){
            User user = JSON.parseObject(message, User.class);
            System.out.println(user);
        }

    }
}