Kafka(八) 使用JAVA代码编写生产者向kafka发送数据，编写消费者消费数据_java中kafka生产者发送一条数据库记录

一。使用JAVA向kafaka发送数据

 先在服务器端启动消费者监听，

kafka-console-consumer.sh --bootstrap-server localhost:9092 --topic test

再运行下边生产者代码我们在上边的服务器端会收到JAVA客户端发送的数据

添加pom依赖

  <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
        <version>2.3.0</version>
    </dependency>

生产者代码

package kafaka;
 
import org.apache.kafka.clients.producer.Callback;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
 
import java.util.Properties;
 
public class ProducerHelloworld {
    public static void main(String[] args) {
        // 1. 创建用于连接Kafka的Properties配置
 
        String topic = "test";
        Properties props = new Properties();
        props.put("bootstrap.servers", "192.168.20.101:9092");
        props.put("acks", "all");
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
 
        // 2. 创建一个生产者对象KafkaProducer
        KafkaProducer<String, String> producer = new KafkaProducer<String, String>(props);
 
            // 二、带回调函数异步方式
            producer.send(new ProducerRecord<String, String>("test", null,  "wjm"), new Callback() {
 
                public void onCompletion(RecordMetadata metadata, Exception exception) {
                    if(exception != null) {
                        System.out.println("发送消息出现异常");
                    }
                    else {
                        String topic = metadata.topic();
                        int partition = metadata.partition();
                        long offset = metadata.offset();
 
                        System.out.println("发送消息到Kafka中的名字为" + topic + "的主题，第" + partition + "分区，第" + offset + "条数据成功!");
                    }
                }
            });
 
 
        // 5. 关闭生产者
        producer.close();
    }
 
 
 
}

二。使用JAVA编写消费者

建立消费者代码

package kafaka;
 
 
 
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.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;
 
import java.util.Collections;
import java.util.Properties;
import java.util.Random;
 
 
public class KafaTest {
 
    public static String topic = "test";
 
    public static void main(String[] args) {
        new Thread(()-> new Producer().execute()).start();
        new Thread(()-> new Consumer().execute()).start();
    }
 
    public static class Consumer {
 
        private void execute() {
            Properties p = new Properties();
            p.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.20.101:9092");
            p.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
            p.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
            p.put(ConsumerConfig.GROUP_ID_CONFIG, topic);
 
            KafkaConsumer<String, String> kafkaConsumer = new KafkaConsumer<>(p);
            // 订阅消息
            kafkaConsumer.subscribe(Collections.singletonList(topic));
 
            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()));
                }
            }
        }
    }
 
 
    public static class Producer {
 
        private void execute() {
            Properties p = new Properties();
            //kafka地址，多个地址用逗号分割
            p.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "192.168.20.101:9092");
            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<>(topic, msg);
                    kafkaProducer.send(record);
                    System.out.println("消息发送成功:" + msg);
                    Thread.sleep(500);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                kafkaProducer.close();
            }
        }
 
    }
}

 首先我们运行消费者代码,接着在服务器上

使用生产者命令，生产数据kafka-console-producer.sh --broker-list localhost:9092 --topic test

发送数据

最后在代码的console端可以看到在服务器上发送的数据