简单kafka的java程序创建生产者和消费者

简单kafka的java程序创建生产者和消费者

1.预置条件

Kafka基础安装使用

2.创建一个springboot工程

2.1 引入相关依赖

<?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.xyd</groupId>
    <artifactId>test-kafka</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
    </parent>

    <properties>
        <java.version>1.8</java.version>
        <kafka.version>2.0.0</kafka.version>
        <scala.version>2.11</scala.version>
        <lombik.version>1.18.8</lombik.version>
        <junit.version>4.11</junit.version>
    </properties>

    <dependencies>
        <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>

        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka-clients</artifactId>
            <version>${kafka.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka_${scala.version}</artifactId>
            <version>${kafka.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.zookeeper</groupId>
                    <artifactId>zookeeper</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

    </dependencies>

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


</project>

2.2创建生产者

package com.example.kafkatest.producer;

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 java.util.Properties;

public class ProducerTest {
    private static final String brokerList = "localhost:9092";

    private static final String topic = "hello";
    public static void main(String[] args) {
        //设置配置项
        Properties properties = new Properties();

        //设置key和value的序列化
        properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
        properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());

        //设置重试次数
        properties.put(ProducerConfig.RETRIES_CONFIG, 10);

        //设置集群地址
        properties.put("bootstrap.servers", brokerList);

        //创建生产者
        KafkaProducer<String, String> kafkaProducer = new KafkaProducer(properties);

        //设置topic及消息
        ProducerRecord<String,String> record = new ProducerRecord<>(topic, "kafka-demo", "hhh");

        //消息发送
        kafkaProducer.send(record);

        //关闭生产者
        kafkaProducer.close();
    }
}

2.3启动验证

前提条件是机器上相关的kafka和zookeeper服务已经启动，具体参考第一节预置条件，并且kafka已经创建了相关的topic主题
启动该类的main方法

在命令窗口上开启的消费者窗口查看

2.4创建消费者

package com.example.kafkatest.consumer;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;

import java.time.Duration;
import java.util.Collections;
import java.util.Properties;

public class ConsumerTest {
    private static final String brokerList = "localhost:9092";

    private static final String topic = "hello";

    private static final String groupId = "group.demo";

    public static void main(String[] args) {

        //设置配置项
        Properties properties = new Properties();

        //设置key和value的序列化
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());

        //设置集群地址
        properties.put("bootstrap.servers", brokerList);

        //设置groupId
        properties.put("group.id", groupId);

        KafkaConsumer consumer = new KafkaConsumer(properties);

        //订阅主题
        consumer.subscribe(Collections.singletonList(topic));

        //设置监听消费
        while (true){
            ConsumerRecords<String, String> consumerRecords = consumer.poll(Duration.ofSeconds(1));
            for (ConsumerRecord<String, String> record:consumerRecords){
                System.out.println(record.value());
            }
        }

    }
}

2.5 启动验证

启动消费者，循环输出下面语句

启动生产发送一条消息，查看消费者输出