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Apache Kafka是一个开源分布式事件流平台，也是当前系统开发中流行的高性能消息队列服务，数千家公司使用它来实现高性能数据管道、流分析、数据集成和关键任务应用程序。
Kafka 可以很好地替代更传统的消息代理。消息代理的使用原因多种多样（将处理与数据生产者分离开来、缓冲未处理的消息等）。与大多数消息系统相比，Kafka 具有更好的吞吐量、内置分区、复制和容错能力，这使其成为大规模消息处理应用程序的良好解决方案。
Java工具类
此基于kafka客户端的工具类，提供基础的消息发送与监听功能。
pom.xml
<!-- 集成kafka --><dependency><groupId>org.springframework.kafka</groupId><artifactId>spring-kafka</artifactId></dependency><dependency><groupId>org.apache.kafka</groupId><artifactId>kafka-streams</artifactId><version>2.2.2</version></dependency><dependency><groupId>org.apache.kafka</groupId><artifactId>kafka-clients</artifactId><version>2.2.2</version></dependency>KafkaUtils.java
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.clients.producer.RecordMetadata;
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.concurrent.Future;/*** @Description kafka工具类，提供消息发送与监听*/
public class KafkaUtils {/*** 获取实始化KafkaStreamServer对象* @return*/public static KafkaStreamServer bulidServer(){return new KafkaStreamServer();}/*** 获取实始化KafkaStreamClient对象* @return*/public static KafkaStreamClient bulidClient(){return new KafkaStreamClient();}public static class KafkaStreamServer{KafkaProducer<String, String> kafkaProducer = null;private KafkaStreamServer(){}/*** 创建配置属性* @param host* @param port* @return*/public KafkaStreamServer createKafkaStreamServer(String host, int port){String bootstrapServers = String.format("%s:%d", host, port);if (kafkaProducer != null){return this;}Properties properties = new Properties();//kafka地址，多个地址用逗号分割properties.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);properties.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);properties.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);kafkaProducer = new KafkaProducer<>(properties);return this;}/*** 向kafka服务发送生产者消息* @param topic* @param msg* @return*/public Future<RecordMetadata> sendMsg(String topic, String msg){ProducerRecord<String, String> record = new ProducerRecord<String, String>(topic, msg);Future<RecordMetadata> future = kafkaProducer.send(record);System.out.println("消息发送成功:" + msg);return future;}/*** 关闭kafka连接*/public void close(){if (kafkaProducer != null){kafkaProducer.flush();kafkaProducer.close();kafkaProducer = null;}}}public static class KafkaStreamClient {KafkaConsumer<String, String> kafkaConsumer = null;private KafkaStreamClient(){}/*** 配置属性,创建消费者* @param host* @param port* @return*/public KafkaStreamClient createKafkaStreamClient(String host, int port, String groupId){String bootstrapServers = String.format("%s:%d", host, port);if (kafkaConsumer != null){return this;}Properties properties = new Properties();//kafka地址，多个地址用逗号分割properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);properties.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);kafkaConsumer = new KafkaConsumer<String, String>(properties);return this;}/*** 客户端消费者拉取消息，并通过回调HeaderInterface实现类传递消息* @param topic* @param headerInterface*/public void pollMsg(String topic, HeaderInterface headerInterface) {kafkaConsumer.subscribe(Collections.singletonList(topic));while (true) {ConsumerRecords<String, String> records = kafkaConsumer.poll(100);for (ConsumerRecord<String, String> record : records) {try{headerInterface.execute(record);}catch(Exception e){e.printStackTrace();}}}}/*** 关闭kafka连接*/public void close(){if (kafkaConsumer != null){kafkaConsumer.close();kafkaConsumer = null;}}}@FunctionalInterfaceinterface HeaderInterface{void execute(ConsumerRecord<String, String> record);}/*** 测试示例* @param args* @throws InterruptedException*/public static void main(String[] args) throws InterruptedException {//生产者发送消息
// KafkaStreamServer kafkaStreamServer = KafkaUtils.bulidServer().createKafkaStreamServer("127.0.0.1", 9092);
// int i=0;
// while (i<10) {
// String msg = "Hello," + new Random().nextInt(100);
// kafkaStreamServer.sendMsg("test", msg);
// i++;
// Thread.sleep(100);
// }
// kafkaStreamServer.close();
// System.out.println("发送结束");System.out.println("接收消息");KafkaStreamClient kafkaStreamClient = KafkaUtils.bulidClient().createKafkaStreamClient("127.0.0.1", 9092, "consumer-45");kafkaStreamClient.pollMsg("test", new HeaderInterface() {@Overridepublic void execute(ConsumerRecord<String, String> record) {System.out.println(String.format("topic:%s,offset:%d,消息:%s", record.topic(), record.offset(), record.value()));}});}
}
