这是我的程序
package kafkaConsumer;
import org.apache.kafka.clients.consumer.*;
import org.apache.kafka.clients.producer.*;
import org.apache.kafka.common.serialization.LongSerializer;
import org.apache.kafka.common.serialization.StringSerializer;
import org.apache.kafka.common.serialization.LongDeserializer;
import org.apache.kafka.common.serialization.StringDeserializer;
import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Properties;
import java.util.Scanner;
import java.util.concurrent.Future;
public class KafkaConsumerExample {
private final static String INTOPIC = "my-intopic";
private final static String OUTTOPIC = "my-outtopic";
private final static String BOOTSTRAP_SERVERS = "192.168.10.10:9092";
private static Producer<Long, String> createProducer(String bootstrapServers) {
Properties props = new Properties();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ProducerConfig.CLIENT_ID_CONFIG, "KafkaProducerExample");
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, LongSerializer.class.getName());
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class.getName());
return new KafkaProducer<>(props);
}
private static Consumer<Long, String> createConsumer(String intopic, String bootstrapServers) {
final Properties props = new Properties();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "KafkaConsumerExample");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, LongDeserializer.class.getName());
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
props.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, "1");
// Create the consumer using props.
final Consumer<Long, String> consumer = new KafkaConsumer<>(props);
// Subscribe to the topic.
consumer.subscribe(Collections.singletonList(intopic));
return consumer;
}
static boolean run(
Consumer<Long, String> consumer, Producer<Long, String> producer,
String inTopic, String outTopic) throws InterruptedException {
String valueToSend;
long keyToUse;
if (consumer == null) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter key> ");
keyToUse = sc.nextLong();
valueToSend = sc.nextLine();
System.out.print("Enter value> ");
valueToSend = sc.nextLine();
} else {
Duration delta = Duration.ofSeconds(1);
ConsumerRecords<Long, String> consumerRecords = consumer.poll(delta);
while (consumerRecords.count() == 0) {
consumerRecords = consumer.poll(delta);
}
ConsumerRecord<Long, String> record = consumerRecords.iterator().next();
keyToUse = record.key();
valueToSend = record.value();
if (producer != null)
System.out.println("Got key = " + keyToUse + " and value = " + valueToSend);
}
if (producer == null) {
System.out.println("key = " + keyToUse + " and value = " + valueToSend);
} else {
try {
System.out.println("Creating ProducerRecord");
final ProducerRecord<Long, String> record =
new ProducerRecord<>(outTopic, keyToUse, valueToSend);
System.out.println("Calling producer.send");
Future<RecordMetadata> sent = producer.send(record);
System.out.println("Calling sent.get");
RecordMetadata metadata = sent.get();
System.out.println("Calling flush");
producer.flush();
System.out.println("After flush");
} catch (Exception e) {
System.out.println("Exception sending message: " + e.getMessage());
}
}
return !valueToSend.equals("STOP");
}
public static void usage() {
System.out.println(System.getProperty("sun.java.command"));
System.out.println();
System.out.println("Usage parameters: [--intopic name] [--outtopic name] [--bootstrap-servers servers]");
System.exit(1);
}
public static void main(String... args) throws Exception {
String inTopic = INTOPIC;
String outTopic = OUTTOPIC;
String bootstrapServers = BOOTSTRAP_SERVERS;
for (int i = 0; i < args.length; ++i) {
if (args[i].equals("--intopic")) {
if (i == args.length - 1) {
usage();
}
inTopic = args[++i];
} else if (args[i].equals("--outtopic")) {
if (i == args.length - 1) {
usage();
}
outTopic = args[++i];
} else if (args[i].equals("--bootstrap-servers")) {
if (i == args.length - 1) {
usage();
}
bootstrapServers = args[++i];
} else {
usage();
}
}
final Consumer<Long, String> consumer;
if (inTopic.equals("stdin")) {
consumer = null;
} else {
consumer = createConsumer(inTopic, bootstrapServers);
}
final Producer<Long, String> producer;
if (outTopic.equals("stdout")) {
producer = null;
} else {
producer = createProducer(bootstrapServers);
}
while (true) {
if (!run(consumer, producer, inTopic, outTopic)) {
break;
}
}
if (consumer != null)
consumer.close();
if (producer != null)
producer.close();
}
}
我在Windows和Linux上运行它。在某些计算机上，它运行良好，但是在其他计算机上，特别是在不是kafka机器的Linux机器上，它始终会给我这个错误：
Exception sending message: org.apache.kafka.common.errors.TimeoutException: Topic outtopic not present in metadata after 60000 ms.
当尝试通过run()函数（尤其是句子RecordMetadata metadata = sent.get()）发送消息时，会发生这种情况。
此kafka安装程序允许自动创建新主题。实际上，如果我在--outtopic参数中输入新名称，即使发送消息失败，也会创建该主题。
任何线索为何？我在配置中缺少什么？
谢谢
西蒙
答案 0 :(得分：2)
192.168.10.10:9092
这似乎是内部IP。检查您无法访问的客户端是否在其网络范围内，即它们是否可以访问该IP。
尝试从客户端计算机进行telnet。
telnet 192.168.10.10 9092
如果您无法telnet，请提供客户可以访问的IP，并在advertised.listeners中确保相同。
还要检查您的advertised.listeners配置。当我们连接到bootstrap.servers中给定的URL时，该URL通常应与advertised.listeners配置中的URL保持一致。
不存在主题元数据意味着您的客户端无法获取有关给定主题的任何信息，即无法通过给定的bootstrap.servers属性获取元数据。