kafka例子

    <dependencies>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka_2.13</artifactId>
            <version>2.7.0</version>
        </dependency>
    </dependencies>

生产者

package com.test.producer;
 
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;
 
import java.util.Properties;
 
public class MyProducer {
 
    public static void main(String[] args) {
 
        Properties properties = new Properties();
 
        properties.put("bootstrap.servers", "localhost:9092");
        // ack
        properties.put("acks", "all");
        // 重试次数
        properties.put("retries", 1);
        // 批次大小
        properties.put("batch.size", 16384);
        // 等待时间
        properties.put("linger.ms", 1);
        // 缓冲区大小
        properties.put("buffer.memory", 33554432);
        // 设置数据key和value的序列化处理类
        properties.put("key.serializer", StringSerializer.class);
        properties.put("value.serializer", StringSerializer.class);
 
        KafkaProducer<String, String> produce = new KafkaProducer<>(properties);
 
        for (int i=0; i < 2; i++) {
            produce.send(new ProducerRecord<>("test","key-"+i,"value--" + i));
        }
 
        produce.close();
 
    }
}

消费者

package com.test.consumer;
 
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.serialization.StringDeserializer;
 
import java.time.Duration;
import java.util.Arrays;
import java.util.Properties;
 
public class MyConsumer {
 
    public static void main(String[] args) {
 
        Properties properties = new Properties();
 
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,"localhost:9092");
        // 自动提交
        properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,true);
        // 提交延时
        properties.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG,"1000");
        // 反序列化
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        // 消费者组
        properties.put(ConsumerConfig.GROUP_ID_CONFIG,"bigdata");
 
        // 重置消费者的offset(换组、offset过期)
        properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG,"earliest");
 
        KafkaConsumer<String, String> consumer = new KafkaConsumer<String, String>(properties);
 
        // 订阅主题
        consumer.subscribe(Arrays.asList("test"));
 
        // 获取数据
        while (true){
            ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
 
            for(ConsumerRecord<String,String> record: records){
                System.out.println("key:" + record.key() + "" + ",value:" +record.value());
 
            }
        }
 
    }
}

带有callback的生产者

package com.test.producer;
 
import org.apache.kafka.clients.producer.*;
import org.apache.kafka.common.serialization.StringSerializer;
 
import java.util.Properties;
 
public class CallbackProducer {
 
    public static void main(String[] args) {
 
        Properties properties = new Properties();
 
        properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,"localhost:9092");
        properties.put("key.serializer", StringSerializer.class);
        properties.put("value.serializer", StringSerializer.class);
 
        KafkaProducer<String, String> producer = new KafkaProducer<String, String>(properties);
 
        for (int i=0; i < 10; i++) {
            producer.send(new ProducerRecord<>("test","1","tt--" + i), (metadata, exception) -> {
                if (exception == null){
                    System.out.println(metadata.partition() + "--" + metadata.offset()) ;
                } else {
                    exception.printStackTrace();
                }
            });
        }
 
        producer.close();
 
    }
 
}