我想知道，如果kafka服务器不在线，我怎么能抓住异常呢 我试着如下：
import org.apache.kafka.clients.producer.*;
import org.apache.kafka.common.serialization.LongSerializer;
import org.apache.kafka.common.serialization.StringSerializer;
import java.util.Properties;
import java.util.concurrent.ExecutionException;
public class KafkaProducerClient {
private final static String TOPIC = "test";
private final static String BOOTSTRAP_SERVERS = "localhost:9092";
private static Producer<String, String> createProducer() {
Properties props = new Properties();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG,
BOOTSTRAP_SERVERS);
props.put(ProducerConfig.CLIENT_ID_CONFIG, "KafkaExampleProducer");
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG,
LongSerializer.class.getName());
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG,
StringSerializer.class.getName());
return new KafkaProducer<>(props);
}
public static void main(String[] args) {
final Producer<String, String> producer = createProducer();
try {
final ProducerRecord<String, String> record = new ProducerRecord<>(TOPIC, "key", "Hello value ");
RecordMetadata metadata = producer.send(record).get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
producer.flush();
producer.close();
}
}
}
我有以下错误：
09:50:59.271 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Node -1 disconnected.
09:50:59.271 [kafka-producer-network-thread | KafkaExampleProducer] WARN org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Connection to node -1 could not be established. Broker may not be available.
09:50:59.271 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.322 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.373 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.423 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.474 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.525 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.576 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.626 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.677 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.727 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.778 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.829 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.880 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.931 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:50:59.982 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:51:00.033 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Give up sending metadata request since no node is available
09:51:00.084 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Initialize connection to node localhost:9092 (id: -1 rack: null) for sending metadata request
09:51:00.084 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.clients.NetworkClient - [Producer clientId=KafkaExampleProducer] Initiating connection to node localhost:9092 (id: -1 rack: null)
09:51:00.085 [kafka-producer-network-thread | KafkaExampleProducer] DEBUG org.apache.kafka.common.network.Selector - [Producer clientId=KafkaExampleProducer] Connection with localhost/127.0.0.1 disconnected
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
at org.apache.kafka.common.network.PlaintextTransportLayer.finishConnect(PlaintextTransportLayer.java:50)
at org.apache.kafka.common.network.KafkaChannel.finishConnect(KafkaChannel.java:106)
at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:444)
at org.apache.kafka.common.network.Selector.poll(Selector.java:398)
at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:460)
at org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:239)
at org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:163)
at java.lang.Thread.run(Thread.java:748)
正如您所看到的，错误从未被发现。 我做错了什么？