集成 SpringBoot

SpringBoot 是一个在 JavaEE 开发中非常常用的组件。可以用于 Kafka 的生产者，也可以 用于 SpringBoot 的消费者。

1）在 IDEA 中安装 lombok 插件

在 Plugins 下搜索 lombok 然后在线安装即可，安装后注意重启

2）SpringBoot 环境准备

（1）创建一个 Spring Initializr

注意：有时候 SpringBoot 官方脚手架不稳定，我们切换国内地址 https://start.aliyun.com

（2）项目名称 springboot

（4）检查自动生成的配置文件

<?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 https://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>2.6.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.atguigu</groupId>
    <artifactId>springboot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot</name>
    <description>springboot</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>org.springframework.kafka</groupId>
            <artifactId>spring-kafka</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

3.1 SpringBoot 生产者

（1）修改 SpringBoot 核心配置文件 application.yml，添加生产者相关信息

spring:
  application:
    name: atguigu-springboot-kafka
  kafka:
    bootstrap-servers: hadoop102:9092,hadoop103:9092,hadoop104:9092
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer

（2）创建 controller 从浏览器接收数据, 并写入指定的 topic

package com.atguigu.springboot.controller;

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

@RestController
public class ProducerController {
    /**
     *  Kafka 模板用来向 kafka 发送数据
     */
    @Autowired
    private KafkaTemplate<String, String> kafka;

    @RequestMapping("/atguigu")
    public String data(String msg) {
        kafka.send("first", msg);
        return "ok";
    }
}

（3）给/atguigu 接口发送数据：http://localhost:8080/atguigu?msg=hello

3.2 SpringBoot 消费者

（1）修改 SpringBoot 核心配置文件 application.propeties

spring:
  application:
    name: atguigu-springboot-kafka
  kafka:
    bootstrap-servers: hadoop102:9092,hadoop103:9092,hadoop104:9092
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer
    consumer:
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      group-id: atguigu

（2）创建类消费 Kafka 中指定 topic 的数据

package com.atguigu.springboot.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.KafkaListener;

@Slf4j
@Configuration
public class KafkaConsumer {
    /**
     * 指定要监听的topic
     *
     * @param msg 收到的value
     */
    @KafkaListener(topics = "first")
    public void consumeTopic(String msg) {
        log.info("收到的信息: {}", msg);
    }
}