kafka consumer demo

package 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 java.util.ArrayList;
import java.util.Properties;


public class ConsumerTest {
    public static void main (String arg[]) {
        Properties properties = getConsumerProperties();
        KafkaConsumer<String,String> comsumer = new KafkaConsumer(properties);


        // 订阅主题
        comsumer.subscribe(new ArrayList<String>());


        // 获取数据
        ConsumerRecords<String,String> records = comsumer.poll(1000);


        // 遍历处理数据
        for (ConsumerRecord<String,String> record : records) {
            System.out.println(record.key()+ record.value());
        }
        
        // 关闭消费者
        comsumer.close();


     /*   // 一般情况下消费者会一直尝试拉取消息并消费消息，所以获取数据和处理数据需要阻塞住（自旋）
        while (true) {
            ConsumerRecords<String,String> records = comsumer.poll(1000);
            // 遍历处理数据
            for (ConsumerRecord<String,String> record : records) {
                System.out.println(record.key()+ record.value());
            }
        }*/


    }


    public static Properties getConsumerProperties() {
        Properties properties = new Properties();


        // 连接的集群
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"xxxxxx");
        // 消费者组
        properties.put(ConsumerConfig.GROUP_ID_CONFIG,"groupID");
        // 开启自动提交
        properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,"true");
        // 自动提交延迟时间
        properties.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG,"10000");
        // 消费者 offset 消费策略
        properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG,"earliest/latest");
        // key - value 反序列化
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");


        return  properties;
    }
}