运行环境

Linux CentOS

JDK8

Zookeeper

Kafka

JDK

Kafka从2.0.0版本就不再支持JDK7及以下版本

Zookeeper

分布式协调系统,Zookeeper是安装Kafka集群的必要组件，Kafka通过Zookeeper来实施对元数据信息的管理，包括集群、broker、主题、分区等内容。

服务器演示

启动zookeeper和kafka

## 启动zookeeper
./bin/kafka-server-start.sh config/server.properties &

## 启动kafka
./bin/kafka-server-start.sh config/server.properties &

## 查看kafka是否启动
jps

创建Topic(topic-demo)

bin/kafka-topics.sh --zookeeper localhost:2181/kafka --create --topic topic-demo --replication-factor 1 --partitions 1

创建Consumer

bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic topic-demo

创建Producer

bin/kafka-console-producer.sh --broker-list localhost:9092 --topic topic-demo

代码演示

生产者类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;
import java.util.Random;

public class Producer {

    public static final String brokerList = "ip:9092";

    public static final String topic = "topic-demo";

    public static Properties initConfig(){
        Properties properties = new Properties();
        properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerList);
        return properties;
    }

    public static void main(String[] args) {
        Properties properties = initConfig();
        KafkaProducer<String, String> producer = new KafkaProducer<>(properties);

        try {
            int i = 0;
            while (i <10){
                String msg = "Hello," + new Random().nextInt(100);
                //消息对象
                ProducerRecord<String, String> record = new ProducerRecord<String, String>(topic, msg);
                //发送
                producer.send(record);
                System.out.println("消息发送成功:" + msg);
                Thread.sleep(500);
                i++;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            producer.close();
        }
    }
}

消费者类Consumer

import lombok.extern.slf4j.Slf4j;
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;
import java.util.concurrent.atomic.AtomicBoolean;

@Slf4j
public class Consumer {

    public static final String brokerList = "ip:9092";

    public static final String topic = "topic-demo";

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

    public static final AtomicBoolean isRunning = new AtomicBoolean(true);

    public static Properties initConfig() {
        Properties properties = new Properties();
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, brokerList);
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        properties.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        return properties;
    }

    public static void main(String[] args) {
        Properties properties = initConfig();

        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(properties);
        // 订阅消息
        consumer.subscribe(Collections.singletonList(topic));

        try {
            while (isRunning.get()) {
                ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
                for (ConsumerRecord<String, String> record : records) {
                    System.out.println(String.format("topic:%s,offset:%d,消息:%s",
                            record.topic(), record.offset(), record.value()));
                }
            }
        } catch (Exception e) {
            log.error(e.getMessage());
        } finally {
            consumer.close();
        }
    }
}