Kafka Java Api操作

JDK1.8

Linux下安装好kafka，这里使用的是版本是kafka_2.11-2.4.1

Windows下安装好IDEA

新建Maven工程

pom.xml依赖

        
            org.apache.kafka
            kafka-clients
            2.4.1
        

新建包org.example

新建类：SimpleProducer.java、SimpleConsumer.java

生产者代码SimpleProducer.java

package org.example;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;

import java.util.Properties;

public class SimpleProducer {

    public static void main(String[] args) {
        String topicName = "Hello-Kafka";
        Properties props = new Properties();

        props.put("bootstrap.servers", "node1:9092");
        props.put("acks", "all");
        props.put("retries", 0);
        props.put("batch.size", 16384);
        props.put("linger.ms",1);
        props.put("buffer.memory", 33554432);
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

        KafkaProducer producer = new KafkaProducer<>(props);
        for (int i =0; i<10; i++){
            String key = Integer.toString(i);
            String value = Integer.toString(i);
            producer.send(new ProducerRecord<>(topicName, key, value));
        }
        System.out.println("Message sent successfully");
        producer.close();
    }

}

消费者代码SimpleConsumer.java

package org.example;

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;

import java.util.Arrays;
import java.util.Properties;

public class SimpleConsumer {
    public static void main(String[] args) {
        String topicName = "Hello-Kafka";
        Properties props = new Properties();

        props.put("bootstrap.servers","node1:9092");
        props.put("group.id","test");
        props.put("enable.auto.commit","true");
        props.put("auto.commit.interval.ms","1000");
        props.put("session.timeout.ms","30000");
        props.put("key.deserializer",
                "org.apache.kafka.common.serialization.StringDeserializer");//注意是StringDeserializer
        props.put("value.deserializer",
                "org.apache.kafka.common.serialization.StringDeserializer");
        KafkaConsumer consumer = new KafkaConsumer<>(props);
        consumer.subscribe(Arrays.asList(topicName));
        System.out.println("Subscribed to topic：" + topicName);
        while (true){
            ConsumerRecords records = consumer.poll(1000);
            for (ConsumerRecord record : records) {
                System.out.printf("offset = %d, key = %s, value = %sn",
                        record.offset(), record.key(), record.value());
            }
        }
    }
}

提示：相关属性的理解，可以查看kafka文档：Kafka 中文文档 - ApacheCN

测试

创建主题Hello-Kafka

[hadoop@node1 ~]$ kafka-topics.sh --create --zookeeper localhost:2181/kafka --replication-factor 1 --partitions 1 --topic Hello-Kafka

查看主题

[hadoop@node1 ~]$ kafka-topics.sh --list --zookeeper localhost:2181/kafka

运行消费者SimpleConsumer.java

 此时如果有生产者生产数据，在消费者控制台将看到信息输出

运行生产者SimpleProducer.java

生产者发送消息后，消费者控制台将有如下输出

 注意：截图offset不是从0开始，因为截图时不是第一次运行生产者代码。

在命令行生产消息

[hadoop@node1 kafka]$ kafka-console-producer.sh --broker-list localhost:9092 --topic Hello-Kafka
>hello
>world
​
​

消费者终端输出

offset = 30, key = null, value = hello
offset = 31, key = null, value = world

demo代码：kafka-api-demo: kafka-api-demo

完成！enjoy it!