Kafka消费者api编写教程

1.基本属性配置

输入new Properties().var 回车

//创建属性Properties properties = new Properties();//连接集群properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"node1:9092,node2:9092");//反序列化properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class.getName());//指定消费者组idproperties.put(ConsumerConfig.GROUP_ID_CONFIG,"KK");

2.创建消费者

输入new KafkaConsumer<String,String>(properties).var 回车选择消费者名称

//创建消费者KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(properties);

3.订阅主题/分区

3.1订阅主题

   输入new ArrayList<String,String>().var 回车修改变量名为topics

        //创建一个数组列表变量接收topics值ArrayList<String> topics = new ArrayList<>();//指定要订阅的主题topics.add("customers");//订阅主题kafkaConsumer.subscribe(topics);

3.2订阅分区

    输入new ArrayList<TopicPartition>().var 回车选择变量名为topicsPartitions

4.消费数据

//消费数据while (true){//if (flag  == true) flag 标志位置//break;//}生产中退出循环的位置；ConsumerRecords<String, String> consumerRecords = kafkaConsumer.poll(Duration.ofSeconds(1));//将消费的信息输出到控制台,输入consumerRecords.for回车，进行对consumerRecords循环遍历for (ConsumerRecord<String,String> consumerRecord : consumerRecords){System.out.println(consumerRecord);}}

5.运行MyConsumer，通过生产者api发送消息

输出台上可以看到输出的都是订阅的主题/分区的信息

6.完整代码

package com.ljr.kafka.replay;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.common.TopicPartition;
import org.apache.kafka.common.serialization.StringDeserializer;import java.time.Duration;
import java.util.ArrayList;
import java.util.Properties;public class MyConsumer {public static void main(String[] args) {//创建属性Properties properties = new Properties();//连接集群properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"node1:9092,node2:9092");//反序列化properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class.getName());//指定消费者组idproperties.put(ConsumerConfig.GROUP_ID_CONFIG,"KK");//创建消费者KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(properties);/*//订阅主题//创建一个数组列表变量接收topics值ArrayList<String> topics = new ArrayList<>();//指定要订阅的主题topics.add("customers");//订阅主题kafkaConsumer.subscribe(topics);*///订阅分区//创建一个数组列表变量接收主题分区值ArrayList<TopicPartition> topicPartitions = new ArrayList<>();//指定要订阅的分区topicPartitions.add(new TopicPartition("customers",2));//订阅分区kafkaConsumer.assign(topicPartitions);//消费数据while (true){//if (flag  == true) flag 标志位置//break;//}生产中退出循环的位置；ConsumerRecords<String, String> consumerRecords = kafkaConsumer.poll(Duration.ofSeconds(1));//将消费的信息输出到控制台，输入consumerRecords.for 回车 对consumerRecords循环遍历for (ConsumerRecord<String,String> consumerRecord : consumerRecords){System.out.println(consumerRecord);}}}
}