[英]Are there any problems with this way of starting an infinite loop in a Spring Boot application?
我有一個Spring Boot應用程序,它需要處理一些Kafka流數據。 我在CommandLineRunner
類中添加了一個無限循環,該循環將在啟動時運行。 那里有一個可以喚醒的卡夫卡消費者。 我用Runtime.getRuntime().addShutdownHook(new Thread(consumer::wakeup));
添加了一個關閉掛鈎Runtime.getRuntime().addShutdownHook(new Thread(consumer::wakeup));
。 我會遇到任何問題嗎? 在春季,有沒有更慣用的方法? 我應該改用@Scheduled
嗎? 下面的代碼刪除了特定的Kafka實現內容,但另有說明。
import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.errors.WakeupException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;
import java.time.Duration;
import java.util.Properties;
@Component
public class InfiniteLoopStarter implements CommandLineRunner {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Override
public void run(String... args) {
Consumer<AccountKey, Account> consumer = new KafkaConsumer<>(new Properties());
Runtime.getRuntime().addShutdownHook(new Thread(consumer::wakeup));
try {
while (true) {
ConsumerRecords<AccountKey, Account> records = consumer.poll(Duration.ofSeconds(10L));
//process records
}
} catch (WakeupException e) {
logger.info("Consumer woken up for exiting.");
} finally {
consumer.close();
logger.info("Closed consumer, exiting.");
}
}
}
我不確定您是否會遇到任何問題,但是有點臟-Spring確實很好地支持與Kafka一起使用,因此我傾向於這樣做(網絡上有很多文檔,但是不錯的是: https : //www.baeldung.com/spring-kafka )。
您需要以下依賴項:
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>2.2.2.RELEASE</version>
</dependency>
配置非常簡單,將@EnableKafka
批注添加到配置類中,然后設置Listener和ConsumerFactory bean
配置完成后,您可以輕松設置使用者,如下所示:
@KafkaListener(topics = "topicName")
public void listenWithHeaders(
@Payload String message,
@Header(KafkaHeaders.RECEIVED_PARTITION_ID) int partition) {
System.out.println("Received Message: " + message"+ "from partition: " + partition);
}
實現看起來還可以,但不能使用CommandLineRunner。 CommandLineRunner僅在啟動時用於運行某些任務。 從設計的角度來看,它不是很優雅。 我寧願在kafka中使用spring集成適配器組件。 您可以在這里找到示例https://github.com/raphaelbrugier/spring-integration-kafka-sample/blob/master/src/main/java/com/github/rbrugier/esb/consumer/Consumer.java 。
為了回答我自己的問題,我看了一下Kafka集成庫(例如Spring-Kafka和Spring Cloud Stream),但是與Confluent的Schema Registry的集成尚未完成或對我來說不是很清楚。 對於原語來說,這已經足夠簡單了,但是對於通過架構注冊表驗證的類型化Avro對象,我們就需要它。 我現在基於Spring Boot的答案實施了一個與Kafka無關的解決方案-在部署時啟動后台線程的最佳方法
最終代碼如下所示:
@Component
public class AccountStreamConsumer implements DisposableBean, Runnable {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
private final AccountService accountService;
private final KafkaProperties kafkaProperties;
private final Consumer<AccountKey, Account> consumer;
@Autowired
public AccountStreamConsumer(AccountService accountService, KafkaProperties kafkaProperties,
ConfluentProperties confluentProperties) {
this.accountService = accountService;
this.kafkaProperties = kafkaProperties;
if (!kafkaProperties.getEnabled()) {
consumer = null;
return;
}
Properties props = new Properties();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, kafkaProperties.getBootstrapServers());
props.put(AbstractKafkaAvroSerDeConfig.SCHEMA_REGISTRY_URL_CONFIG, confluentProperties.getSchemaRegistryUrl());
props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, kafkaProperties.getSecurityProtocolConfig());
props.put(SaslConfigs.SASL_MECHANISM, kafkaProperties.getSaslMechanism());
props.put(SaslConfigs.SASL_JAAS_CONFIG, PlainLoginModule.class.getName() + " required username=\"" + kafkaProperties.getUsername() + "\" password=\"" + kafkaProperties.getPassword() + "\";");
props.put(KafkaAvroDeserializerConfig.SPECIFIC_AVRO_READER_CONFIG, true);
props.put(ConsumerConfig.GROUP_ID_CONFIG, kafkaProperties.getAccountConsumerGroupId());
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, KafkaAvroDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, KafkaAvroDeserializer.class);
consumer = new KafkaConsumer<>(props);
consumer.subscribe(Collections.singletonList(kafkaProperties.getAccountsTopicName()));
Thread thread = new Thread(this);
thread.start();
}
@Override
public void run() {
if (!kafkaProperties.getEnabled())
return;
logger.debug("Started account stream consumer");
try {
//noinspection InfiniteLoopStatement
while (true) {
ConsumerRecords<AccountKey, Account> records = consumer.poll(Duration.ofSeconds(10L));
List<Account> accounts = new ArrayList<>();
records.iterator().forEachRemaining(record -> accounts.add(record.value()));
if (accounts.size() != 0)
accountService.store(accounts);
}
} catch (WakeupException e) {
logger.info("Account stream consumer woken up for exiting.");
} finally {
consumer.close();
}
}
@Override
public void destroy() {
if (consumer != null)
consumer.wakeup();
logger.info("Woke up account stream consumer, exiting.");
}
}
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