kafka筆記一

（本人是kafka小白，想把自己的筆記記錄下來，慢慢學習，逐漸成長）

一、首先安裝kafka叢集，最近最新版本是1.0，下載kafka1.0安裝包，解壓縮，修改配置檔案，安裝，測試，詳見另一篇部落格筆記：kafka叢集安裝部署
二、完成kafka訊息訂閱三劍客：producer生產者、broker中介軟體、consumer消費者
三、利用kafkaAPI編寫生產消費demo

（1）建立maven專案，pom檔案中新增kafka依賴包

        <dependency>
            <groupId>org.apache.kafka</groupId
 
>
            <artifactId>kafka-clients</artifactId>
            <version>1.0.0</version>
        </dependency>

（2）寫生產者程式

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer
 
.Producer;

import java.util.Properties;

public class kafka_producer {
    public static void main(String[] args){
        //配置資訊
        Properties props = new Properties();
        props.put("bootstrap.servers", "寫上自己的叢集IP：port")
        props.put("acks", "all");
        props.put("retries", 0);
        props.put
 
("batch.size", 16384);
        props.put("linger.ms", 1);
        props.put("buffer.memory", 33554432);
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        //例項化生產者物件
        Producer<String, String> producer = new KafkaProducer<String,String>(props);
        for(int i=0;i<=50;i++){
            String s = "send message : "+i;
            producer.send(new ProducerRecord<String,String>("test1",Integer.toString(i), s));
        }

        producer.close();
    }
}

（3）現在在後端切到kafka安裝目錄的bin目錄下，執行kafka的消費者命令

./kafka-console-consumer.sh --bootstrap-server 你的ip:port --topic 你的topic --from-beginning

執行生產者程式，觀察到後端kafka服務中consumer在消費訊息。

注：保證topic一致，保證kafka叢集正常啟動。

（4）消費者demo

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;

import java.util.Arrays;
import java.util.Properties;

public class kafka_consumer {
    public static void main(String[] args){

        Properties props = new Properties();
        props.put("bootstrap.servers", "your ip:port")
        props.put("group.id", "my_group");
        props.put("enable.auto.commit", "true");
        props.put("auto.commit.interval.ms", "1000");
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");

        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(props);

        consumer.subscribe(Arrays.asList("test1"));

        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());
        }
    }
}

依據kafkaAPI， 簡單的實現了生產消費程序，後續會繼續學習，共勉！