1.Kafka 介绍

• Apache Kafka® is a distributed streaming platform.

• 官网地址

2.maven 依赖

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka_2.12</artifactId>
    <version>0.10.2.0</version>
</dependency>

<dependency>
   <groupId>org.apache.kafka</groupId>
   <artifactId>kafka-clients</artifactId>
   <version>0.10.2.0</version>
</dependency>

3.手动创建一个 Topic

• 安装 Kafka 的步骤省略
• 确保已经安装了Kafka 和 zookeeper(尽量不用Kafka自带的zk)

1) 启动zookeeper服务 ：bin/zkServer.sh start conf/zoo.cfg

2）启动kafka服务 ：

    前台启动：kafka-server-start.sh $KAFKA_HOME/config/server.properties

    后台启动：nohup bin/kafka-server-start.sh $KAFKA_HOME/config/server.properties >logs/catalina.log &

3) 创建topic : bin/kafka-topics.sh --create --zookeeper localhost:2181/kafka --replication-factor 1 --partitions 1 --topic partition-topic

4) 查看zookeeper下的topic数量 ： 

    bin/kafka-topics.sh --list --zookeeper localhost:2181/kafka

    bin/kafka-topics.sh --describe --zookeeper localhost:2181/kafka --topic partition-topic

5）发送消息 ：bin/kafka-console-producer.sh --broker-list localhost:9092 --topic partition-topic

6）消费消息 ：bin/kafka-console-consumer.sh --zookeeper localhost:2181/kafka --from-beginning --topic partition-topic

4.Producer

package com.zxr.micro.socket.kafka;

import org.apache.kafka.clients.producer.*;
import java.util.Properties;
import java.util.concurrent.Future;

public class ProducerDemo {

    private static final String TOPIC = "partition-topic";
    private static final String BOOTSTRAP_SERVERS = "127.0.0.1:9092";

    private static KafkaProducer initProducer() {
        Properties props = new Properties();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, BOOTSTRAP_SERVERS);
        props.put(ProducerConfig.ACKS_CONFIG, "all");
        props.put(ProducerConfig.RETRIES_CONFIG, 1);
        props.put(ProducerConfig.BATCH_SIZE_CONFIG, 16384);
        props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
        props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, 33554432);
        props.put(ProducerConfig.REQUEST_TIMEOUT_MS_CONFIG, 3000);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
        return new KafkaProducer(props);
    }

    @SuppressWarnings("unchecked")
    public static Future sendOne(String key, String value) {
        return initProducer().send(new ProducerRecord<>(TOPIC, key, value));
    }

    public static void main(String[] args) throws Exception {
        Future aa = ProducerDemo.sendOne("03", "dd");
        System.out.println(">>>>>>>>>>: " + aa.get().toString());
        Thread.sleep(3000);

        Future bb = ProducerDemo.sendOne("04", "ee");
        System.out.println(">>>>>>>>>>: " + bb.get().toString());
        Thread.sleep(3000);

        Future cc = ProducerDemo.sendOne("03", "ff");
        System.out.println(">>>>>>>>>>: " + cc.get().toString());
        Thread.sleep(3000);
    }
}

• Producer Java API

5.Consumer

package com.zxr.micro.socket.kafka;

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 java.util.*;

public class ConsumerDemo {

    private static final String TOPIC = "partition-topic";
    private static final String BOOTSTRAP_SERVERS = "127.0.0.1:9092";

    public static void main(String[] args) {
        Properties props = new Properties();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, BOOTSTRAP_SERVERS);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, "test");
        props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, 50000);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
        props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "1000");
        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
        consumer.subscribe(Collections.singletonList(TOPIC));
        while (true) {
            ConsumerRecords<String, String> records = consumer.poll(100);
            for (ConsumerRecord<String, String> record : records)
                System.out.printf("offset = %d, key = %s, value = %s%n", record.offset(), record.key(), record.value());
        }
    }
}

• Consumer Java API

6.PS 下篇介绍 Kafka 原理