Calculate delta Offsets Kafka Java

问题

In a spring project i used Kafka and now I want to make a method which takes "TopicName" and "GroupeId" as parameters and calculate the difference between "Lastoffsets of the topic partitions" and the "offsets consumed by the group"

for the lastOffsets i get it now i need to get the consumed offsets to calculate the difference

public ResponseEntity<Offsets> deltaoffsets (@RequestParam( name = "groupId") String groupId, @RequestParam( name = "topic") String topic) {
        Map<String,Object> properties = (Map) kafkaLocalConsumerConfig.get("kafkaLocalConsumerConfig");
        properties.put("group.id", groupId);
        properties.put("enable.auto.commit", "true");
        List<TopicPartition> partition=new ArrayList<>();

        KafkaConsumer<String, RefentialToReload> kafkaLocalConsumer = new KafkaConsumer<>(properties);

        Map<String, List<PartitionInfo>> topics = kafkaLocalConsumer.listTopics();
        List<PartitionInfo> partitionInfos = topics.get(topic);

        if (partitionInfos == null) {
            log.warn("Partition information was not found for topic");
        }

    else {
            for (PartitionInfo partitionInfo : partitionInfos) {
                TopicPartition topicPartition = new TopicPartition(topic, partitionInfo.partition());
                partition.add(topicPartition);
                log.info("partition assigned to kafkaLocalConsumer");
            }
        }
        //get lastOffsets of the topicPartition
        Map<TopicPartition,Long> OffsetsTopicpartition = kafkaLocalConsumer.endOffsets(kafkaLocalConsumer.assignment());
        //here i need to get consumed offsets 
}

回答1:

beginningOffsets() is the first offsets, not the last.

You can use an AdminClient - here is an example that displays the current and end offsets...

@Bean
public ApplicationRunner runner(KafkaAdmin admin, ConsumerFactory<String, String> cf) throws Exception {
    return args -> {
    try (
            AdminClient client = AdminClient.create(admin.getConfig());
            Consumer<String, String> consumer = cf.createConsumer("group", "clientId", "");
        ) {
        Collection<ConsumerGroupListing> groups = client.listConsumerGroups()
                .all()
                .get(10, TimeUnit.SECONDS);
        groups.forEach(group -> {
            Map<TopicPartition, OffsetAndMetadata> map = null;
            try {
                map = client.listConsumerGroupOffsets(group.groupId())
                        .partitionsToOffsetAndMetadata()
                        .get(10, TimeUnit.SECONDS);
            }
            catch (InterruptedException e) {
                e.printStackTrace();
                Thread.currentThread().interrupt();
            }
            catch (ExecutionException e) {
                e.printStackTrace();
            }
            catch (TimeoutException e) {
                e.printStackTrace();
            }
            Map<TopicPartition, Long> endOffsets = consumer.endOffsets(map.keySet());
            map.forEach((tp, off) -> {
                System.out.println("group: " + group + " tp: " + tp
                        + " current offset: " + off.offset()
                        + " end offset: " + endOffsets.get(tp));
            });
        });
    }
    };
}

来源：https://stackoverflow.com/questions/65566470/calculate-delta-offsets-kafka-java