Kafka：指定时间消费

朴灿烈づ我的快乐病毒、 2024-03-25 22:51 71阅读 0赞

**需求：**

在生产环境中，会遇到最近消费的几个小时数据异常，想重新按照时间消费。例如要求按照时间消费前一天的数据，怎么处理？

import org.apache.kafka.clients.consumer.*;
    import org.apache.kafka.common.TopicPartition;
    import org.apache.kafka.common.serialization.StringDeserializer;
    
    import java.time.Duration;
    import java.util.*;
    
    public class CustomConsumerSeekTime {
    
        public static void main(String[] args) {
    
            // 0 配置信息
            Properties properties = new Properties();
    
            // 连接
            properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"192.168.25.129:9092,192.168.25.129:9092");
    
            // 反序列化
            properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
            properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
    
            // 组id
            properties.put(ConsumerConfig.GROUP_ID_CONFIG,"test3");
    
            // 1 创建消费者
            // KafkaConsumer<K, V> 
            // 由于消息形式是 key value 为 "", "hello"
            // 所以泛型K为key为String类型 泛型V为传递消息的类型，此处发送字符串用String类型
            KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(properties);
    
            // 2 订阅主题
            ArrayList<String> topics = new ArrayList<>();
            topics.add("test");
            kafkaConsumer.subscribe(topics);
    
            // ===================================此处==============================================
    
            // 指定位置进行消费
            Set<TopicPartition> assignment = kafkaConsumer.assignment();
    
            //  保证分区分配方案已经制定完毕
            // 因为消费者初始化与broker通信进行分区分配需要一定的时间
            while (assignment.size() == 0){
                kafkaConsumer.poll(Duration.ofSeconds(1));
    
                assignment = kafkaConsumer.assignment();
            }
    
            // 希望把时间转换为对应的offset
            HashMap<TopicPartition, Long> topicPartitionLongHashMap = new HashMap<>();
    
            // 封装对应集合
            for (TopicPartition topicPartition : assignment) {
                // 每个分区对应一天前的数据，从此刻一天前
                topicPartitionLongHashMap.put(topicPartition,System.currentTimeMillis() - 1 * 24 * 3600 * 1000);
            }
    
            Map<TopicPartition, OffsetAndTimestamp> topicPartitionOffsetAndTimestampMap = kafkaConsumer.offsetsForTimes(topicPartitionLongHashMap);
    
            // 遍历每个分区，对每个分区设置消费时间。指定消费的offset
            for (TopicPartition topicPartition : assignment) {
    
                OffsetAndTimestamp offsetAndTimestamp = topicPartitionOffsetAndTimestampMap.get(topicPartition);
                
                if (offsetAndTimestamp != null) {
                    // 将时间转成offset去消费
                    kafkaConsumer.seek(topicPartition, offsetAndTimestamp.offset());
                }
    
            }
    
            // ==============================止此======================================
    
            // 3  消费数据
            while (true){
    
                ConsumerRecords<String, String> consumerRecords = kafkaConsumer.poll(Duration.ofSeconds(1));
    
                for (ConsumerRecord<String, String> consumerRecord : consumerRecords) {
    
                    System.out.println(consumerRecord);
                }
            }
        }
    }