11 消息生产者向topic中发送消息

1. 创建一个maven工程并引入依赖

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.6.RELEASE</version>
    </parent>

    <groupId>com.paic</groupId>
    <artifactId>kafkaDemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.2.6.RELEASE</version>
        </dependency>

        <!--引入kafka客户端依赖-->
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>3.0.0</version>
        </dependency>

    </dependencies>

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

</project>

2. 直接上代码

package com.atguigu.kafka.controller;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Properties;

@RestController
@RequestMapping("kafka")
public class CustomProducerController {

    @RequestMapping("sendMsg")
    public void sendMsg(){
        System.out.println("ready to send msg");
        Properties properties = new Properties();
        // 连接集群 bootstrap.servers
        properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,"localhost:9092");
        // 指定对应的key和value的序列化类型 key.serializer
        properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,StringSerializer.class.getName());

        //1.创建kafka生产者对象
        KafkaProducer<String, String> kafkaProducer = new KafkaProducer<>(properties);
        // 2 发送数据
        for (int i = 0; i < 5; i++) {
            kafkaProducer.send(new ProducerRecord<>("ums-cardbin","learn always "+i));
        }

        // 3 关闭资源
        kafkaProducer.close();
    }


}

注意：这里是因为在本地没有直接连接上linux中的kafka,因此新建了一个springboot的工程，在controller中写入一个访问的路径，向kafka中发送消息

[root@localhost ~]# curl http://localhost:8081/kafka/sendMsg