kafka生产者与消费者API的简单应用

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

import java.io.IOException;
import java.util.Properties;


public class Demo5 {
    public static void main(String[] args) throws IOException {
        Properties properties = new Properties();
        properties.load(Demo5.class.getClassLoader().getResourceAsStream("producer.properties"));
        KafkaProducer producer = new KafkaProducer<>(properties);
        //创建要发送的数据(叫做生产的记录producerecord)
        ProducerRecord record = new ProducerRecord<>("hadoop", "nihao");

        //生产者生产消息
        for (int i = 0;i<20;i++){
            //生产者发送信息
            producer.send(record);
        }
        producer.close();
    }
}

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


import java.io.IOException;
import java.util.Arrays;
import java.util.Properties;


public class Demo6 {
    public static void main(String[] args) throws IOException {
        Properties properties = new Properties();
        properties.load(Demo6.class.getClassLoader().getResourceAsStream("consumer.properties"));
        KafkaConsumer consumer = new KafkaConsumer<>(properties);
        //消费者要想消费，需要在好到那个主题,也就是先订阅(subscribe)那个主题
        consumer.subscribe(Arrays.asList("hadoop"));
        //消费者开始消费数据
        while (true){
            ConsumerRecords records = consumer.poll(1000);//获取数据
            //数据不止一个所以需要遍历
            for (ConsumerRecord record : records) {//这个遍历的类型是ConsumerRecord，不要弄错了
               System.out.printf("offset = %d, key = %s, value = %s%n", record.offset(), record.key(), record.value());
            }
        }

    }
}