kafka producerrecord如何发送

要使用Kafka ProducerRecord发送消息，您需要遵循以下步骤：

1. 添加Kafka客户端依赖项：首先，确保在项目的pom.xml文件中添加了Kafka客户端的依赖项。对于Maven项目，添加以下依赖项：

    org.apache.kafka
    kafka-clients
    2.8.0

2. 创建Kafka生产者配置：创建一个Kafka生产者配置对象，指定Kafka集群的地址、密钥生成器等配置信息。

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092");
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");

3. 创建Kafka生产者实例：使用配置对象创建一个Kafka生产者实例。

Producer producer = new KafkaProducer<>(props);

4. 创建Kafka ProducerRecord实例：创建一个Kafka ProducerRecord实例，指定主题、键和值。

String topic = "your_topic_name";
String key = "your_key";
String value = "https://www.yisu.com/ask/your_value";
ProducerRecord record = new ProducerRecord<>(topic, key, value);

5. 发送Kafka ProducerRecord：使用Kafka生产者实例发送Kafka ProducerRecord。

producer.send(record, new Callback() {
    @Override
    public void onCompletion(RecordMetadata metadata, Exception exception) {
        if (exception != null) {
            exception.printStackTrace();
        } else {
            System.out.println("Sent record to topic: " + metadata.topic() + ", partition: " + metadata.partition() + ", offset: " + metadata.offset());
        }
    }
});

6. 关闭Kafka生产者：在完成消息发送后，关闭Kafka生产者以释放资源。

producer.close();

将以上代码整合到一个完整的示例中：

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.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecordMetadata;

import java.util.Properties;

public class KafkaProducerExample {
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringSerializer");

        Producer producer = new KafkaProducer<>(props);

        String topic = "your_topic_name";
        String key = "your_key";
        String value = "https://www.yisu.com/ask/your_value";
        ProducerRecord record = new ProducerRecord<>(topic, key, value);

        producer.send(record, new Callback() {
            @Override
            public void onCompletion(RecordMetadata metadata, Exception exception) {
                if (exception != null) {
                    exception.printStackTrace();
                } else {
                    System.out.println("Sent record to topic: " + metadata.topic() + ", partition: " + metadata.partition() + ", offset: " + metadata.offset());
                }
            }
        });

        producer.close();
    }
}

请注意，您需要根据实际情况替换your_topic_name、your_key和your_value。