KafkaProducer无法成功将消息发送到队列中 [英] KafkaProducer not successfully sending message into the queue

问题描述

我已经在Windows PC上构建了一个小型测试环境，并写下了以下代码来测试kafka(使用org.apache.kafka的kafka_2.10:0.9.0.1).

I have built a small testing environment on my Windows PC and write down the following code for testing kafka (using kafka_2.10:0.9.0.1 from org.apache.kafka).

package iii.functiontesting;

import java.text.ParseException;
import java.util.Properties;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerRecord;


/**
 * Hello world!
 *
 */
public class test4
{
    public static void main( String[] args ) throws ParseException
    {
        Properties producerProps=new Properties();
        producerProps.put("bootstrap.servers", "localhost:9092");
        producerProps.put("serializer.class",org.apache.kafka.common.serialization.StringSerializer.class.getName());
        producerProps.put("key.serializer",org.apache.kafka.common.serialization.StringSerializer.class.getName());
        producerProps.put("value.serializer",org.apache.kafka.common.serialization.StringSerializer.class.getName());
        producerProps.put("request.required.acks","1");
        KafkaProducer<String,String> kafkawriter= new KafkaProducer<String,String>(producerProps);
        ProducerRecord<String,String> msg=new ProducerRecord<>("TEST3","ImKey","teststring1");
        kafkawriter.send(msg);
    }
}

我使用以下命令检查消息是否正确写入队列

I use the following command to check whether the message is correctly written into the queue

D:\ Work \ kafkaenv \ kafka_2.10-0.9.0.1 \ bin \ windows>.\ kafka-console-consumer.bat --zookeeper localhost:2181 --topic TEST3 --from-beginning

D:\Work\kafkaenv\kafka_2.10-0.9.0.1\bin\windows>.\kafka-console-consumer.bat --zookeeper localhost:2181 --topic TEST3 --from-beginning

但是，我发现kafka-console-consumer没有显示任何内容.

However, I found that the kafka-console-consumer shows nothing.

我怀疑我的kafka服务器无法正常运行，因此我使用console-producer进行测试.

I have doubted that my kafka server doesn't run properly, so I use console-producer to test.

D:\ Work \ kafkaenv \ kafka_2.10-0.9.0.1 \ bin \ windows>.\ kafka-console-producer.bat --broker-list localhost:9092 --topic TEST3

D:\Work\kafkaenv\kafka_2.10-0.9.0.1\bin\windows>.\kafka-console-producer.bat --broker-list localhost:9092 --topic TEST3

aaaaa

这次，我可以看到aaaaa清楚地显示在控制台用户下. 我不知道会发生什么. 谁能帮我吗?

This time I can see the aaaaa is clearly shown under the console-consumer. I cannot figure out what happens. Can anyone help me?

推荐答案

您必须在终止程序之前调用KafkaProducer#flush [或] KafkaProducer#close方法.

You have to call either KafkaProducer#flush [or] KafkaProducer#close method before terminating the program.

实际上，生产者在将记录发送给代理之前先对记录进行缓冲.请参见 Kafka Producer配置

Actually, the producer buffers the records before sending it to the broker. See buffer.memory and batch.size in the Kafka Producer configuration

kafkawriter.send(msg);
kafkawriter.close();

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