Kafka消費者Demo

依賴包：

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

原始碼：

package com.kafka.jdbc;

import org.apache.kafka.clients.consumer.*;
 
import org.apache.kafka.common.TopicPartition;

import java.util.*;

public class DefineCustomeConsumer {

    private static Map<TopicPartition, Long> currentOffset = new HashMap<>();

    public static void main(String[] args) throws Exception {
        // 建立配置資訊
        Properties props = new
 
 Properties();
        // Kafka 叢集
        props.put("bootstrap.servers", "10.168.4.76:9093");
        // 消費者組，只要 group.id 相同，就屬於同一個消費者組
        props.put("group.id", "group_gong");
        // 關閉自動提交 offset
        props.put("enable.auto.commit", "false");
        // Key 和 Value 的反序列化類
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        props.put(
 
"value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        // 建立一個消費者
        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
        // 消費者訂閱主題
        consumer.subscribe(Arrays.asList("topic_gong"), new ConsumerRebalanceListener() {
            // 該方法會在 Rebalance 之前呼叫
            @Override
            public void onPartitionsRevoked(Collection<TopicPartition> partitions) {
                commitOffset(currentOffset);
            }

            // 該方法會在 Rebalance 之後呼叫
            @Override
            public void onPartitionsAssigned(Collection<TopicPartition> partitions) {
                currentOffset.clear();
                for (TopicPartition partition : partitions) {
                    consumer.seek(partition, getOffset(partition));
                    // 定位到最近提交的 offset 位置繼續消費
                }
            }
        });
//        while (true) {
            ConsumerRecords<String, String> records = consumer.poll(1000);// 消費者拉取資料
            for (ConsumerRecord<String, String> record : records) {
                System.out.printf("offset = %d, key = %s, value= %s%n", record.offset(), record.key(), record.value());
                currentOffset.put(new TopicPartition(record.topic(), record.partition()), record.offset());
            }
            commitOffset(currentOffset);// 非同步提交
            Thread.sleep(1000);
//        }
    }

    // 獲取某分割槽的最新 offset
    private static long getOffset(TopicPartition partition) {
        return 0;
    }

    // 提交該消費者所有分割槽的 offset
    private static void commitOffset(Map<TopicPartition, Long> currentOffset) {
    }

}