Kafka 消费 topic 最近 n 条消息

迷南。 2021-12-21 10:09 324阅读 0赞

package com.cloudera.kafkademo;
    
    import org.apache.kafka.clients.admin.AdminClient;
    import org.apache.kafka.clients.admin.DescribeTopicsResult;
    import org.apache.kafka.clients.admin.TopicDescription;
    import org.apache.kafka.clients.consumer.*;
    import org.apache.kafka.common.KafkaFuture;
    import org.apache.kafka.common.Node;
    import org.apache.kafka.common.TopicPartition;
    import org.apache.kafka.common.TopicPartitionInfo;
    
    import java.util.*;
    import java.util.logging.Logger;
    public class ReceiveLatestMessageUtils { 
    
        private static final Logger logger = Logger.getLogger(ReceiveLatestMessageUtils.class.getName());
        public static void receiveLatestMessage(Map<String, Object> kafkaParams, String topic, Integer count) { 
            logger.info("create KafkaConsumer");
    
            final KafkaConsumer consumer = new KafkaConsumer<>(kafkaParams);
    
            AdminClient adminClient = AdminClient.create(kafkaParams);
    
            try { 
                DescribeTopicsResult topicResult = adminClient.describeTopics(Arrays.asList(topic));
    
                Map<String, KafkaFuture<TopicDescription>> descMap = topicResult.values();
    
                Iterator<Map.Entry<String, KafkaFuture<TopicDescription>>> itr = descMap.entrySet().iterator();
    
                while (itr.hasNext()) { 
                    Map.Entry<String, KafkaFuture<TopicDescription>> entry = itr.next();
                    logger.info("key: " + entry.getKey());
                    List<TopicPartitionInfo> topicPartitionInfoList = entry.getValue().get().partitions();
    
                    for (TopicPartitionInfo topicPartitionInfo : topicPartitionInfoList) { 
                        consumerAction(topicPartitionInfo, consumer, topic, count);
                    }
                }
                consumer.subscribe(Arrays.asList(topic));
                while (true) { 
                    ConsumerRecords<String,String> records = consumer.poll(100);
                    for (ConsumerRecord<String,String> record : records) { 
                        System.out.printf("read offset =%d, key=%s , value= %s, partition=%s\n",
                                record.offset(), record.key(), record.value(), record.partition());
                    }
                }
            } catch (Exception ex) { 
                ex.printStackTrace();
                logger.info("when calling kafka output error." + ex.getMessage());
            } finally { 
                adminClient.close();
                consumer.close();
            }
        }
    
        private static void consumerAction(TopicPartitionInfo topicPartitionInfo, KafkaConsumer<String, String> consumer, String topic, Integer count) { 
    
            int partitionId = topicPartitionInfo.partition();
    
            Node node = topicPartitionInfo.leader();
    
            TopicPartition topicPartition = new TopicPartition(topic, partitionId);
    
            Map<TopicPartition, Long> mapBeginning = consumer.beginningOffsets(Arrays.asList(topicPartition));
    
            Iterator<Map.Entry<TopicPartition, Long>> beginIterator = mapBeginning.entrySet().iterator();
            long beginOffset = 0;
    
            //mapBeginning只有一个元素，因为Arrays.asList(topicPartition)只有一个topicPartition
            while (beginIterator.hasNext()) { 
                Map.Entry<TopicPartition, Long> beginEntry = beginIterator.next();
                beginOffset = beginEntry.getValue();
            }
    
            Map<TopicPartition, Long> mapEnd = consumer.endOffsets(Arrays.asList(topicPartition));
            Iterator<Map.Entry<TopicPartition, Long>> endIterator = mapEnd.entrySet().iterator();
    
            long lastOffset = 0;
            while (endIterator.hasNext()) { 
                Map.Entry<TopicPartition, Long> endEntry = endIterator.next();
                lastOffset = endEntry.getValue();
            }
    
            long expectedOffSet = lastOffset - count;
            expectedOffSet = expectedOffSet > 0 ? expectedOffSet : 1;
            logger.info("Leader of partitionId: " + partitionId + " is " + node + ". expectedOffSet:" + expectedOffSet
                    + "， beginOffset:" + beginOffset + ", lastOffset:" + lastOffset);
    
            consumer.commitSync(Collections.singletonMap(topicPartition, new OffsetAndMetadata(expectedOffSet)));
        }
    
        public static void main(String... args) throws Exception { 
            Map<String, Object> kafkaParams = new HashMap<String, Object>();
            kafkaParams.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "cdh01:9092,cdh02:9092,cdh03:9092");
            kafkaParams.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
            kafkaParams.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
            kafkaParams.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "latest");
            kafkaParams.put(ConsumerConfig.GROUP_ID_CONFIG, "my-consumer");
            kafkaParams.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
            kafkaParams.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, 10);
    
    // 1. 减少 max.poll.records
    // 2. 增加 session.timeout.ms
    // 3. 减少 auto.commit.interval.ms
            kafkaParams.put(ConsumerConfig.MAX_POLL_INTERVAL_MS_CONFIG, 500);
            kafkaParams.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "1000");
            kafkaParams.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, "10000");
    
            receiveLatestMessage(kafkaParams, "test", 5);
    
        }
    }

pom.xml

<dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>           
    	# 此版本没有 AdminClient
       
        <version>0.11.0.2</version>
    </dependency>