springboot使用kafka的过程

<dependencies>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka-clients</artifactId>
        <version>3.6.0</version> <!-- 版本按需选，建议用较新稳定版 -->
    </dependency>
</dependencies>

import org.apache.kafka.clients.producer.*;
import java.util.Properties;
public class KafkaProducerDemo {
    public static void main(String[] args) {
        // 1. 配置 Kafka 连接、序列化等参数
        Properties props = new Properties();
        props.put("bootstrap.servers", "localhost:9092"); // Kafka 集群地址
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer"); // 键的序列化器
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer"); // 值的序列化器
        // 2. 创建 Producer 实例
        Producer<String, String> producer = new KafkaProducer<>(props);
        // 3. 构造消息（指定主题、键、值）
        String topic = "test_topic"; // 要发送到的主题，需提前在 Kafka 创建或允许自动创建
        String key = "key1";
        String value = "Hello, Kafka from IDEA!";
        ProducerRecord<String, String> record = new ProducerRecord<>(topic, key, value);
        // 4. 发送消息（异步发送 + 回调处理结果）
        producer.send(record, new Callback() {
            @Override
            public void onCompletion(RecordMetadata metadata, Exception exception) {
                if (exception != null) {
                    System.err.println("消息发送失败：" + exception.getMessage());
                } else {
                    System.out.printf("消息发送成功！主题：%s，分区：%d，偏移量：%d%n", 
                        metadata.topic(), metadata.partition(), metadata.offset());
                }
            }
        });
        // 5. 关闭 Producer（实际生产环境可能在程序结束时或合适时机关闭）
        producer.close();
    }
}

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import java.util.Properties;
public class KafkaProducerExample {
    private final static String TOPIC = "mytopic";
    private final static String BOOTSTRAP_SERVERS = "localhost:9092";
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("bootstrap.servers", BOOTSTRAP_SERVERS);
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        KafkaProducer<String, String> producer = new KafkaProducer<>(props);
        try {
            for (int i = 0; i < 10; i++) {
                String message = "Message " + i;
                producer.send(new ProducerRecord<>(TOPIC, message));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            producer.close();
        }
    }
}

import org.apache.kafka.clients.consumer.*;
import java.time.Duration;
import java.util.Collections;
import java.util.Properties;
public class KafkaConsumerDemo {
    public static void main(String[] args) {
        // 1. 配置 Kafka 连接、反序列化、消费者组等参数
        Properties props = new Properties();
        props.put("bootstrap.servers", "localhost:9092"); // Kafka 集群地址
        props.put("group.id", "test_group"); // 消费者组 ID，同一组内消费者协调消费
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer"); // 键的反序列化器
        props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer"); // 值的反序列化器
        props.put("auto.offset.reset", "earliest"); // 没有已提交偏移量时，从最早消息开始消费
        // 2. 创建 Consumer 实例
        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
        // 3. 订阅主题
        String topic = "test_topic";
        consumer.subscribe(Collections.singletonList(topic));
        // 4. 循环拉取消息（长轮询）
        try {
            while (true) {
                ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
                for (ConsumerRecord<String, String> record : records) {
                    System.out.printf("收到消息：主题=%s，分区=%d，偏移量=%d，键=%s，值=%s%n", 
                        record.topic(), record.partition(), record.offset(), 
                        record.key(), record.value());
                }
                // 手动提交偏移量（也可配置自动提交，生产环境建议手动更可靠）
                consumer.commitSync();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // 5. 关闭 Consumer
            consumer.close();
        }
    }
}

import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import java.util.Collections;
import java.util.Properties;
public class KafkaConsumerExample {
    private final static String TOPIC = "mytopic";
    private final static String BOOTSTRAP_SERVERS = "localhost:9092";
    private final static String GROUP_ID = "mygroup";
    public static void main(String[] args) {
        Properties props = new Properties();
        props.put("bootstrap.servers", BOOTSTRAP_SERVERS);
        props.put("group.id", GROUP_ID);
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
        consumer.subscribe(Collections.singletonList(TOPIC));
        try {
            while (true) {
                ConsumerRecords<String, String> records = consumer.poll(100);
                // 处理接收到的消息
                records.forEach(record -> {
                    System.out.println("Received message: " + record.value());
                });
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            consumer.close();
        }
    }
}