中国品牌网站设计,西安网站建设外包,城乡建设杂志网站,潍坊网站建设科技有限公司在ConsumerConfig这个类中定义了这个属性的默认值#xff0c;如下图 也就是默认值为latest,它的含义是#xff1a;如果没有客户端提交过offset的话#xff0c;当新的客户端消费时#xff0c;把最新的offset设置为当前消费的offset.
默认是自动提交位移的#xff0c;每5秒…在ConsumerConfig这个类中定义了这个属性的默认值如下图 也就是默认值为latest,它的含义是如果没有客户端提交过offset的话当新的客户端消费时把最新的offset设置为当前消费的offset.
默认是自动提交位移的每5秒进行一次提交。可以通过参数配置手动提交。
手动提交offset的示例 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 org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.PartitionInfo;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;import java.time.Duration;
import java.time.temporal.TemporalUnit;
import java.util.*;
import java.util.concurrent.TimeUnit;
/*
设置手动提交offset*/public class KafkaTest08 {private static Properties getProperties(){Properties propertiesnew Properties();properties.setProperty(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());properties.setProperty(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());properties.setProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,xx.xx.xx.xx:9092);properties.setProperty(ConsumerConfig.GROUP_ID_CONFIG,testGroup8);//设置手动提交位移properties.setProperty(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,false);return properties;}public static void main(String[] args) {KafkaConsumerString,String myConsumernew KafkaConsumerString, String(getProperties());myConsumer.subscribe(Arrays.asList(student));int i0;while(true){ConsumerRecordsString,String consumerRecordsmyConsumer.poll(Duration.ofMillis(5000));for(ConsumerRecord record: consumerRecords){System.out.println(record.value());System.out.println(record offset is: record.offset());}myConsumer.commitSync();if(i0){//myConsumer.commitSync();i ;}else {i ;}}}
}
