Java Kafka 消息推送与接收程序代码示例

下面是一个简单的Java程序，用于发送和接收Kafka消息：

发送程序：

import java.util.Properties;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;

public class KafkaProducerExample {
    public static void main(String[] args) {
        String topicName = 'my-topic';
        String bootstrapServers = 'localhost:9092';

        // 设置Kafka生产者的配置属性
        Properties properties = new Properties();
        properties.put('bootstrap.servers', bootstrapServers);
        properties.put('key.serializer', 'org.apache.kafka.common.serialization.StringSerializer');
        properties.put('value.serializer', 'org.apache.kafka.common.serialization.StringSerializer');

        // 创建Kafka生产者
        KafkaProducer<String, String> producer = new KafkaProducer<>(properties);

        // 发送消息
        for (int i = 0; i < 10; i++) {
            String key = 'key-' + i;
            String value = 'value-' + i;
            ProducerRecord<String, String> record = new ProducerRecord<>(topicName, key, value);
            producer.send(record);
        }

        // 关闭Kafka生产者
        producer.close();
    }
}

接收程序：

import java.time.Duration;
import java.util.Collections;
import java.util.Properties;
import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.serialization.StringDeserializer;

public class KafkaConsumerExample {
    public static void main(String[] args) {
        String topicName = 'my-topic';
        String bootstrapServers = 'localhost:9092';
        String groupId = 'my-group';

        // 设置Kafka消费者的配置属性
        Properties properties = new Properties();
        properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        properties.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
        properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
        properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());

        // 创建Kafka消费者
        Consumer<String, String> consumer = new KafkaConsumer<>(properties);

        // 订阅主题
        consumer.subscribe(Collections.singletonList(topicName));

        // 接收消息
        while (true) {
            ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
            records.forEach(record -> {
                System.out.println('Received message: key = ' + record.key() + ', value = ' + record.value());
            });
        }
    }
}

以上程序使用了Apache Kafka的Java客户端库。在发送程序中，我们创建了一个Kafka生产者，并发送了10条消息到指定的主题。在接收程序中，我们创建了一个Kafka消费者，并订阅了指定的主题，然后不断地从Kafka中拉取消息并进行处理。