我刚起床和Kafka0.8beta1一起跑。我有一个非常简单的例子,问题是,我只能得到一个消息消费者的工作,而不是几个。也就是说,runsingleworker()方法可以工作。run()方法无效:
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.consumer.ConsumerConfig;
import kafka.javaapi.consumer.ConsumerConnector;
import java.util.Map;
import java.util.List;
import java.util.HashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.truecar.inventory.worker.core.application.config.AppConfig;
public class ConsumerThreadPool {
private final ConsumerConnector consumer;
private final String topic;
private ExecutorService executor;
private static ApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
public ConsumerThreadPool(String topic) {
consumer = kafka.consumer.Consumer.createJavaConsumerConnector((ConsumerConfig)context.getBean("consumerConfig"));
this.topic = topic;
}
public void shutdown() {
if (consumer != null) consumer.shutdown();
if (executor != null) executor.shutdown();
}
public void run(Integer numThreads) {
Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
topicCountMap.put(topic, numThreads);
Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
List<KafkaStream<byte[], byte[]>> topicListeners = consumerMap.get(topic);
executor = Executors.newFixedThreadPool(numThreads);
for(Integer i = 0; i < numThreads; i++ ){
KafkaStream<byte[], byte[]> stream = topicListeners.get(i);
executor.submit(new Consumer(stream, i));
}
}
public void runSingleWorker(Integer numThreads) {
Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
topicCountMap.put(topic, new Integer(1));
Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
KafkaStream<byte[], byte[]> stream = consumerMap.get(topic).get(0);
ConsumerIterator<byte[], byte[]> it = stream.iterator();
while(true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
while(it.hasNext()){
System.out.println(new String(it.next().message()));
}
}
}
}
在我的玩具消费者里面:
import kafka.consumer.KafkaStream;
import kafka.consumer.ConsumerIterator;
public class Consumer implements Runnable {
private KafkaStream kafkaStream;
private Integer threadNumber;
public Consumer(KafkaStream kafkaStream, Integer threadNumber) {
this.threadNumber = threadNumber;
this.kafkaStream = kafkaStream;
}
public void run() {
ConsumerIterator<byte[], byte[]> it = kafkaStream.iterator();
System.out.println("Created iterator " + it.toString() + " thread number " + threadNumber);
while(true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
break;
}
while(it.hasNext()) {
System.out.println("Thread " + threadNumber + ": " + new String(it.next().message()));
}
}
System.out.println("Shutting down Thread: " + threadNumber);
}
}
问题是,工作人员池无法接收消息:
Created iterator empty iterator thread number 3
Created iterator empty iterator thread number 6
Created iterator empty iterator thread number 9
Created iterator empty iterator thread number 7
Created iterator empty iterator thread number 0
Created iterator empty iterator thread number 0
Created iterator empty iterator thread number 8
Created iterator empty iterator thread number 3
etc...
当我通过product命令行添加消息时,消息在单线程worker版本下打印,但在多流情况下不打印消息。这是怎么回事?我怎样才能解决这个问题?
顺便说一句,kafka 0.8的pom.xml不是有效的pom,也不会获取依赖项,因此这里是一个具有完全依赖项的pom。
<?xml version="1.0" encoding="UTF-8"?>
<project
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://maven.apache.org/POM/4.0.0
http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>group1</groupId>
<artifactId>artifact1</artifactId>
<version>0.1.0</version>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<org.springframework.version>3.2.4.RELEASE</org.springframework.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>3.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka_2.9.2</artifactId>
<version>0.8.0-beta1</version>
</dependency>
<dependency>
<groupId>javax.inject</groupId>
<artifactId>javax.inject</artifactId>
<version>1</version>
</dependency>
<dependency>
<groupId>org.scala-lang</groupId>
<artifactId>scala-library</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.3</version>
</dependency>
<dependency>
<groupId>com.yammer.metrics</groupId>
<artifactId>metrics-core</artifactId>
<version>2.2.0</version>
</dependency>
</dependencies>
<build>
<finalName>inventory-core</finalName>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.0</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>com.truecar.inventory.worker.core.application.Starter</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.dstovall</groupId>
<artifactId>onejar-maven-plugin</artifactId>
<version>1.4.4</version>
<executions>
<execution>
<configuration>
<onejarVersion>0.97</onejarVersion>
<classifier>onejar</classifier>
</configuration>
<goals>
<goal>one-jar</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<pluginRepositories>
<pluginRepository>
<id>onejar-maven-plugin.googlecode.com</id>
<url>http://onejar-maven-plugin.googlecode.com/svn/mavenrepo</url>
</pluginRepository>
</pluginRepositories>
</project>
1条答案
按热度按时间k2arahey1#
也许对提问者来说太迟了,但对其他开发人员可能有用。似乎您只为几个消费者使用了一个分区—这是错误的。引用文件:
由于有许多分区,这仍然平衡了许多使用者示例的负载。但是请注意,使用者示例不能多于分区。
因此,当您考虑消费者时,您应该考虑如何按分区划分消息。在大多数情况下,您应该对它使用一些高级分组,甚至在默认情况下让它是随机的。