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Java操作Kafka（最简单的使用）

java操作kafka非常的简单，然后kafka也提供了很多缺省值，一般情况下我们不需要修改太多的参数就能使用。下面我贴出代码。

pom.xml

<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka-clients</artifactId>
    <version>0.10.2.0</version>
</dependency>
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生产者

package cn.duanjt;
import java.util.Properties;
import java.util.Random;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringSerializer;

public class Producer {
    public static String topic = "duanjt_test";//定义主题
    public static void main(String[] args) throws InterruptedException {
        Properties p = new Properties();
        p.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.23.76:9092,192.168.23.77:9092");//kafka地址，多个地址用逗号分割
        p.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        p.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        KafkaProducer<String, String> kafkaProducer = new KafkaProducer<>(p);
        try {
            while (true) {
                String msg = "Hello," + new Random().nextInt(100);
                ProducerRecord<String, String> record = new ProducerRecord<String, String>(topic, msg);
                kafkaProducer.send(record);
                System.out.println("消息发送成功:" + msg);
                Thread.sleep(500);
            }
        } finally {
            kafkaProducer.close();
        }

    }
}
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注意：

1.kafka如果是集群，多个地址用逗号分割(,)

2.Properties的put方法，第一个参数可以是字符串，如:p.put("bootstrap.servers","192.168.23.76:9092")

3.kafkaProducer.send(record)可以通过返回的Future来判断是否已经发送到kafka，增强消息的可靠性。同时也可以使用send的第二个参数来回调，通过回调判断是否发送成功。

4.p.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);设置序列化类，可以写类的全路径

消费者

package cn.duanjt;
import java.util.Collections;
import java.util.Properties;
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;
public class Consumer {
    public static void main(String[] args) {
        Properties p = new Properties();
        p.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.23.76:9092");
        p.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        p.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        p.put(ConsumerConfig.GROUP_ID_CONFIG, "duanjt_test");
        KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<String, String>(p);
        kafkaConsumer.subscribe(Collections.singletonList(Producer.topic));// 订阅消息
        while (true) {
            ConsumerRecords<String, String> records = kafkaConsumer.poll(100);
            for (ConsumerRecord<String, String> record : records) {
                System.out.println(String.format("topic:%s,offset:%d,消息:%s", //
                        record.topic(), record.offset(), record.value()));
            }
        }
    }
}
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