Introduction Case

Public Static Void Main (String [] ARGS) Throws ExecutionException, InterruptedException { 
         MAP <string, Object> Configs = New HashMap <string, Object> (); 
         // Specify the Broker address used in the initial connection 
         configs.put ("Bootstrap.Servers", "192.168.0.103:9092"); 
         // Specify the serialization class of the key 
         configs.put ("Key.serializer", Integerserializer.class); 
         // Specify the serialization class of value 
         Configs.put ("Value.serializer", StringSerializer.class); 

 // configs.put ("act"); "all"); 
 // configs.put ("Reties", "3"); 

         KafkapRoducer <Integer, String> Producer = New Kafkaproducer <Integer, String> (Configs); 

         // Used to set the user -defined message header field 
         List <header> headers = new arraylist <header> (); 
         Headers.add (New RecordHeader ("BIZ.NAME", "Producer.Demo" .Getbytes ())); 

         Producerrecord <Integer, String> Record = New ProducerRold <Integer, String> ( 
                 "Topic_1", 
                 0, 
                 0, 
                 "Hello Hqk 0", 
                 headers 
         ); 

         // Synchronous confirmation of message 
         FINAL FUTURE <RecordMetAdata> Future = Producer.Send (Record); 
         FINAL RecordMetAdata Metadata = Future.get (); 
         System.out.println ("Theme of the message:" + metadata.topic ()); 
         System.out.println ("partition number of messages: + metadata.partition ()); 
         System.out.println ("Message of Message:" + Metadata.Offset ()); 


         // Close the producer 
         Producer.close (); 
     }

WARN Client session timed out, have not heard from server in 30000ms for sessionid 0x0 (org.apache.zookeeper.ClientCnxn)
Exception in thread "main" kafka.zookeeper.ZooKeeperClientTimeoutException: Timed out waiting for connection while in state: CONNECTING
	at kafka.zookeeper.ZooKeeperClient.waitUntilConnected(ZooKeeperClient.scala:262)
	at kafka.zookeeper.ZooKeeperClient.<init>(ZooKeeperClient.scala:119)
	at kafka.zk.KafkaZkClient$.apply(KafkaZkClient.scala:1881)
	at kafka.admin.TopicCommand$ZookeeperTopicService$.apply(TopicCommand.scala:376)
	at kafka.admin.TopicCommand$.main(TopicCommand.scala:57)
	at kafka.admin.TopicCommand.main(TopicCommand.scala)

Check some of the possible causes:
1. Whether the Zookeeper configured in the Config directory in the Config directory is wrong

Whether the ports of
2.2181 and 9092 are occupied
3. Firewall needs to be closed
4. Connect the Zookeeper port is 2181
5. The parameter of the high version Kafka when creating the theme is not-zookeeper, but-Bootstrap-Server

The last discovery was not

need to be in Kafka’s /config/service.properties, and finally add a sentence to house.name = your own server IP

############################# Group Coordinator Settings #############################

# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
group.initial.rebalance.delay.ms=0

host.name=192.168.0.103

and then restart Kafka to connect again

[Main] Info org.apache.kafka.Clients.producer.producerconfig -Producerconfig Values: 
 Acks = 1 
 batch.size = 16384 
 bootstrap.servers = [192.168.0.103:9092] 
 buffer.Memory = 33554432 
 client.id = 
 compression.type = None 
 Connections.max.idle.ms = 540000 
 enable.idempotence = false 
 interceptor.classes = null 
 Key.serializer = class org.apache.kafkka.Common.Serialization.integerserializer 
 linger.ms = 0 
 max.block.ms = 60000 
 max.in.flight.requests.per.connection = 5 
 max.request.size = 1048576 
 metadata.max.age.ms = 300000 
 metric.reporters = [] 
 metrics.num.samples = 2 
 metrics.Recording.Level = Info 
 metrics.sample.window.ms = 30000 
 Partitioner.Class = class org.apache.kafkka.Clients.producer.internals.DefaultPartitioner 
 Receive.buffer.bytes = 32768 
 reconnect.backoff.max.ms = 1000 
 reconnect.backoff.ms = 50 
 request.timeout.ms = 30000 
 Retries = 0 
 Retry.backoff.ms = 100 
 sasl.jaas.config = null 
 sasl.kerberos.kinit.cmd =/usr/bin/kinit 
 SASL.KERBEROS.MIN.TIME.BEFORE.Rlogin = 6000 
 SASL.KERBEROS.SERVICE.NAME = NULL 
 SASL.KERBEROS.TICKET. Renew.jitter = 0.05 
 SASL.KERBEROS.TICKET. Renew.window.factor = 0.8 
 SASL.MeChanism = gssapi 
 security.protocol = plaintext 
 Send.buffer.bytes = 131072 
 ssl.cipher.suites = null 
 ssl.enabled.protocols = [TLSV1.2, TLSV1.1, TLSV1] 
 ssl.endpoint.Identification.algorithm = Null 
 ssl.Key.password = NULL 
 ssl.keyManager.algorithm = Sunx509 
 ssl.KeyStore.Location = NULL 
 ssl.KeyStore.password = NULL 
 ssl.keystore.type = JKS 
 ssl.protocol = TLS 
 ssl.prvider = null 
 ssl.secure.random.implementation = null 
 ssl.trustManager.algorithm = pkix 
 ssl.trustStore.Location = NULL 
 ssl.trustStore.password = NULL 
 ssl.trustStore.type = JKS 
 Transaction.Timeout.ms = 6000 
 Transactional.id = NULL 
 Value.serializer = Class org.apache.kafka.common.Serialization.StringSerializer 

 [Main] Info org.apache.kafkka.Common.utils.appinfoparser -Kafkka Version: 1.0.2 
 [Main] Info org.apache.kafkka.Common.utils.appinfoparser -Kafka Commitid: 2A121F7B1D402825 
 Theme of the message: Topic_1 
 The partition number of the message: 0 
 Disposal of messages: 8 
 

 Process Finished with EXIT CODE 0

Send it successfully