以下是生产者和消费者的类。什么时候能够生成数据，并且无法使用以下代码使用它。有谁曾经帮助过我吗？我在编码方面做错了吗？我的目标是从消费者那里读取CustomMessage对象并将数据存储在DB中。
在我的cmd提示符中，我为zookeeper打开了5个实例1，为kafka打开了1个实例，为生产者打开了1个，为消费者打开了1个实例。我真的不明白。当我运行生产者和消费者类时，是否需要保持所有实例？
任何指针都非常有用。
提前致谢。
producer class:::
package com.kafka.test.demo;
import java.io.IOException;
import java.util.Properties;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.xml.sax.SAXException;
public class KafkaaProducer {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
Properties props = new Properties();
//customMessage is a pojo object which should be send to the consumer..
CustomMessage customMessage= new CustomMessage();
customMessage.setMessage("hello kafka");
customMessage.setFan("1234213123");
customMessage.setSourceSystem("Dmap");
customMessage.setStatus("Unenrolled");
customMessage.setMessageTyep("Simple Message");
customMessage.setCreatedTime("5");
customMessage.setProcessedTime("6");
customMessage.setRetryCount("3");
props.put("metadata.broker.list", "localhost:9092");
props.put("serializer.class", "kafka.serializer.StringEncoder");
props.put("request.required.acks", "1");
props.put("bootstrap.servers", "localhost:9092,localhost:9093");
//CustomMessageSerializer
props.put("key.serializer","com.kafka.test.demo.CustomMessageSerializer");
props.put("value.serializer", "com.kafka.test.demo.CustomMessageSerializer");
try {
KafkaProducer<String, CustomMessage> producer = new KafkaProducer<String, CustomMessage>(props);
producer.send(new ProducerRecord<String, CustomMessage>("NewMessageTopic", "customMessage",customMessage));
//producer.send(new ProducerRecord<String, CustomMessage>("NewMessageTopic", customMessage));
System.out.println("Message " + "" + " sent !!");
} catch (Exception e) {
e.printStackTrace();
}
}
}
consumer class::
package com.kafka.test.demo;
import java.net.UnknownHostException;
import java.util.Collections;
import java.util.Properties;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
public class KafkaaConsumer {
public static void main(String[] args) throws InterruptedException {
Properties props = new Properties();
props.put("zookeeper.connect", "localhost:2181");
props.put("group.id", "testgroup");
props.put("zookeeper.session.timeout.ms", "4000");
props.put("zookeeper.sync.time.ms", "300");
props.put("rebalance.backoff.ms", "40000");
props.put("bootstrap.servers", "localhost:9092,localhost:9093");
props.put("value.deserializer", "com.kafka.test.demo.CustomMessageDeserializer");
props.put("key.deserializer", "com.kafka.test.demo.CustomMessageDeserializer");
//perisitMessage();
try{
KafkaConsumer<String,CustomMessage> consumer = new KafkaConsumer<String, CustomMessage>(props);
consumer.subscribe(Collections.singletonList("NewMessageTopic"));
while (true) {
ConsumerRecords<String, CustomMessage> messages = consumer.poll(100);
for (ConsumerRecord<String, CustomMessage> message : messages) {
System.out.println("Message received " + message);
}
perisitMessage();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static void perisitMessage() {
// TODO Auto-generated method stub
CustomMessage customMessage = new CustomMessage();
customMessage.setMessage("hello kafka");
customMessage.setFan("1234213123");
customMessage.setSourceSystem("Dmap");
customMessage.setStatus("Unenrolled");
customMessage.setMessageTyep("Simple Message");
customMessage.setCreatedTime("5");
customMessage.setProcessedTime("6");
customMessage.setRetryCount("3");
try {
MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
DB db = mongoClient.getDB("DeviceTrack");
DBCollection msgCollection = db.getCollection("messages");
BasicDBObject document = new BasicDBObject();
document.put("message", customMessage.getMessage());
document.put("fan", customMessage.getFan());
document.put("SourceSystem", customMessage.getSourceSystem());
document.put("RetryCount", customMessage.getRetryCount());
document.put("ProcessedTime", customMessage.getProcessedTime());
document.put("CreatedTime", customMessage.getCreatedTime());
document.put("MessageTyep", customMessage.getMessageTyep());
document.put("Status", customMessage.getStatus());
msgCollection.insert(document);
System.out.println("Inserted in the data in DB succesfully");
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
package com.kafka.test.demo;
import java.util.Map;
import org.apache.kafka.common.serialization.Deserializer;
import com.fasterxml.jackson.databind.ObjectMapper;
public class CustomMessageDeserializer implements Deserializer {
public Object deserialize(String arg0, byte[] arg1) {
ObjectMapper mapper = new ObjectMapper();
System.out.println("arg1"+arg1);
CustomMessage message = null;
try {
message = mapper.readValue(arg1, CustomMessage.class);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(""+message);
return message;
}
public void close() {
// TODO Auto-generated method stub
}
public void configure(Map arg0, boolean arg1) {
// TODO Auto-generated method stub
}
}
package com.kafka.test.demo;
import java.util.Map;
import org.apache.kafka.common.serialization.Serializer;
import com.fasterxml.jackson.databind.ObjectMapper;
public class CustomMessageSerializer implements Serializer {
public byte[] serialize(String arg0, Object arg1) {
byte[] retVal = null;
ObjectMapper objectMapper = new ObjectMapper();
try {
retVal = objectMapper.writeValueAsString(arg1).getBytes();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println("value ::::::"+retVal);
return retVal;
}
public void close() {
// TODO Auto-generated method stub
}
public void configure(Map arg0, boolean arg1) {
// TODO Auto-generated method stub
}
}
package com.kafka.test.demo;
public class CustomMessage {
private String messageId;
private String parentMsgId;
private String fan;
private String message;
private String sourceSystem;
private String status;
private String messageTyep;
private String createdTime;
private String processedTime;
private String retryCount;
/**
* @return the messageId
*/
public String getMessageId() {
return messageId;
}
/**
* @param messageId the messageId to set
*/
public void setMessageId(String messageId) {
this.messageId = messageId;
}
/**
* @return the parentMsgId
*/
public String getParentMsgId() {
return parentMsgId;
}
/**
* @param parentMsgId the parentMsgId to set
*/
public void setParentMsgId(String parentMsgId) {
this.parentMsgId = parentMsgId;
}
/**
* @return the fan
*/
public String getFan() {
return fan;
}
/**
* @param fan the fan to set
*/
public void setFan(String fan) {
this.fan = fan;
}
/**
* @return the message
*/
public String getMessage() {
return message;
}
/**
* @param message the message to set
*/
public void setMessage(String message) {
this.message = message;
}
/**
* @return the sourceSystem
*/
public String getSourceSystem() {
return sourceSystem;
}
/**
* @param sourceSystem the sourceSystem to set
*/
public void setSourceSystem(String sourceSystem) {
this.sourceSystem = sourceSystem;
}
/**
* @return the status
*/
public String getStatus() {
return status;
}
/**
* @param status the status to set
*/
public void setStatus(String status) {
this.status = status;
}
/**
* @return the messageTyep
*/
public String getMessageTyep() {
return messageTyep;
}
/**
* @param messageTyep the messageTyep to set
*/
public void setMessageTyep(String messageTyep) {
this.messageTyep = messageTyep;
}
/**
* @return the createdTime
*/
public String getCreatedTime() {
return createdTime;
}
/**
* @param createdTime the createdTime to set
*/
public void setCreatedTime(String createdTime) {
this.createdTime = createdTime;
}
/**
* @return the processedTime
*/
public String getProcessedTime() {
return processedTime;
}
/**
* @param processedTime the processedTime to set
*/
public void setProcessedTime(String processedTime) {
this.processedTime = processedTime;
}
/**
* @return the retryCount
*/
public String getRetryCount() {
return retryCount;
}
/**
* @param retryCount the retryCount to set
*/
public void setRetryCount(String retryCount) {
this.retryCount = retryCount;
}
}
答案 0 :(得分：0)
您只需要zookeeper和kafka实例。
如果我理解你，你使用“kafka-console-producer”＆amp; “kafka-console-consumer”？他们不需要使用您的Kafka群集。如果您的代码工作，那么应该没问题。如果通过cmd启动kafka需要做很多工作，你可以写一个.bat。
喜欢
:startZK
echo Zookeeper wird gestartet
Start "Zookeper" C:\zookeeper-3.4.9\bin\zkServer.cmd
echo Bitte warten bis Zookeeper gestartet ist.
pause
echo Kafka Wird Gestartet
Start "Kafka" C:\kafka_2.11-0.10.2.0\bin\windows\kafka-server-start.bat C:\kafka_2.11-0.10.2.0\config\server.properties
goto Top
首次查看代码时，它看起来是正确的。 我不知道你只打印你到达system.out的数据吗？
while (true) {
ConsumerRecords<String, CustomMessage> messages = consumer.poll(100);
for (ConsumerRecord<String, CustomMessage> message : messages) {
System.out.println("Message received " + message);<-- just a syso not more :/
}
perisitMessage(); <-- maybe give him the message ?
}
如果你在大纲上看到你的消息？它工作得很好。如果你没有看到任何我今晚可以近距离观察。请给我一个提示。但我没有使用MongoDB的经验。
答案 1 :(得分：0)
是的，您需要运行Zookeeper，然后运行Kafka经纪人，然后启动您的使用者，然后开始生产，您应该在使用者中看到它。
此外，当您使用Custom对象时，我建议使用Jackson序列化为字符串并将其发送。另一方面，您总是可以反序列化它。然后将所有序列化器更改为字符串。