http://kafka.apache.org/07/quickstart.html
和基本的消费者群体示例:
https://cwiki.apache.org/confluence/display/KAFKA/Consumer+Group+Example
我已经编写了Consumer和ConsumerThreadPool,如上所示:
import kafka.consumer.KafkaStream; import kafka.consumer.ConsumerIterator; public class Consumer implements Runnable { private KafkaStream m_stream; private Integer m_threadNumber; public Consumer(KafkaStream a_stream,Integer a_threadNumber) { m_threadNumber = a_threadNumber; m_stream = a_stream; } public void run() { ConsumerIterator<byte[],byte[]> it = m_stream.iterator(); while (it.hasNext()) { System.out.println("Thread " + m_threadNumber + ": " + new String(it.next().message())); } System.out.println("Shutting down Thread: " + m_threadNumber); } }
其他几个方面:我使用spring来管理我的zookeeper:
import javax.inject.Named; import java.util.Properties; import kafka.consumer.ConsumerConfig; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; @Configuration @ComponentScan("com.truecar.inventory.worker.core") public class AppConfig { @Bean @Named("consumerConfig") private static ConsumerConfig createConsumerConfig() { String zookeeperAddress = "127.0.0.1:2181"; String groupId = "inventory"; Properties props = new Properties(); props.put("zookeeper.connect",zookeeperAddress); props.put("group.id",groupId); props.put("zookeeper.session.timeout.ms","400"); props.put("zookeeper.sync.time.ms","200"); props.put("auto.commit.interval.ms","1000"); return new ConsumerConfig(props); } }
我正在使用Maven和OneJar Maven插件进行编译.但是,我编译然后运行生成的一个jar我得到以下错误:
Aug 26,2013 6:15:41 PM org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider registerDefaultFilters INFO: JSR-330 'javax.inject.Named' annotation found and supported for component scanning Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.simontuffs.onejar.Boot.run(Boot.java:340) at com.simontuffs.onejar.Boot.main(Boot.java:166) Caused by: java.lang.NoClassDefFoundError: scala/ScalaObject at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:792) at com.simontuffs.onejar.JarClassLoader.defineClass(JarClassLoader.java:803) at com.simontuffs.onejar.JarClassLoader.findClass(JarClassLoader.java:710) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at com.simontuffs.onejar.JarClassLoader.loadClass(JarClassLoader.java:630) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2521) at java.lang.Class.getDeclaredMethods(Class.java:1845) at org.springframework.core.type.StandardAnnotationMetadata.getAnnotatedMethods(StandardAnnotationMetadata.java:180) at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:222) at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:165) at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:140) at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:282) at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:223) at org.springframework.context.support.AbstractApplicationContext.invokebeanfactoryPostProcessors(AbstractApplicationContext.java:630) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:461) at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:73) at com.truecar.inventory.worker.core.consumer.ConsumerThreadPool.<clinit>(ConsumerThreadPool.java:31) at com.truecar.inventory.worker.core.application.Starter.main(Starter.java:20) ... 6 more Caused by: java.lang.ClassNotFoundException: scala.ScalaObject at com.simontuffs.onejar.JarClassLoader.findClass(JarClassLoader.java:713) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at com.simontuffs.onejar.JarClassLoader.loadClass(JarClassLoader.java:630) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 27 more
现在,我对Kafka知之甚少,对Scala一无所知.我该如何解决?接下来我该怎么办?这是一个已知的问题?我需要其他依赖项吗?这是我的pom.xml中的kafka版本:
<dependency> <groupId>org.apache.kafka</groupId> <artifactId>kafka_2.9.2</artifactId> <version>0.8.0-beta1</version> </dependency>
更新:我联系了Kafka dev邮件列表,他们让我知道了scala依赖项的一些特定版本要求.但是,还有一个未记录的log4j依赖项,这会导致另一个运行时,而不是编译时异常.
Exception in thread "main" java.lang.reflect.InvocationTargetException Caused by: java.lang.NoSuchMethodError: ch.qos.logback.classic.Logger.filterAndLog(Ljava/lang/String;Lorg/slf4j/Marker;Lch/qos/logback/classic/Level;Ljava/lang/String;[Ljava/lang/Object;Ljava/lang/Throwable;)V at org.apache.log4j.Category.log(Category.java:333) at org.apache.commons.logging.impl.Log4JLogger.debug(Log4JLogger.java:177)
另一个更新:
我发现了正确的log4j依赖:
<dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version> </dependency>
但现在我遇到了一个更加神秘的运行时异常:
Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.simontuffs.onejar.Boot.run(Boot.java:340) at com.simontuffs.onejar.Boot.main(Boot.java:166) Caused by: java.lang.NoClassDefFoundError: org/I0Itec/zkclient/IZkStateListener at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:64) at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:66) at kafka.consumer.Consumer$.createJavaConsumerConnector(ConsumerConnector.scala:100) at kafka.consumer.Consumer.createJavaConsumerConnector(ConsumerConnector.scala)
在这一点上,我得到了WTF的那种感觉.所以我添加了另一个依赖:
<dependency> <groupId>com.101tec</groupId> <artifactId>zkclient</artifactId> <version>0.3</version> </dependency>
但是这暴露了另一个运行时异常:
Exception in thread "main" java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at com.simontuffs.onejar.Boot.run(Boot.java:340) at com.simontuffs.onejar.Boot.main(Boot.java:166) Caused by: java.lang.NoClassDefFoundError: com/yammer/metrics/core/Gauge at kafka.consumer.ZookeeperConsumerConnector.createFetcher(ZookeeperConsumerConnector.scala:146) at kafka.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:113) at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:64) at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:66) at kafka.consumer.Consumer$.createJavaConsumerConnector(ConsumerConnector.scala:100) at kafka.consumer.Consumer.createJavaConsumerConnector(ConsumerConnector.scala)
我希望能够让这个婴儿的例子正常运行,但也许这是使用beta产品的代价?也许我应该切换到Apache Active MQ.但这听起来不那么有趣.我错过了什么吗?
解决方法
完整依赖列表如下.请注意,您必须相应地更改scala版本依赖关系到kafka工件的后缀.
<dependency> <groupId>org.scala-lang</groupId> <artifactId>scala-library</artifactId> <version>2.8.0</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.15</version> <exclusions> <exclusion> <groupId>com.sun.jmx</groupId> <artifactId>jmxri</artifactId> </exclusion> <exclusion> <groupId>com.sun.jdmk</groupId> <artifactId>jmxtools</artifactId> </exclusion> <exclusion> <groupId>javax.jms</groupId> <artifactId>jms</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>net.sf.jopt-simple</groupId> <artifactId>jopt-simple</artifactId> <version>3.2</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-simple</artifactId> <version>1.6.4</version> </dependency> <dependency> <groupId>org.scala-lang</groupId> <artifactId>scala-compiler</artifactId> <version>2.8.0</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> <dependency> <groupId>com.yammer.metrics</groupId> <artifactId>metrics-annotation</artifactId> <version>2.2.0</version> </dependency> <dependency> <groupId>org.easymock</groupId> <artifactId>easymock</artifactId> <version>3.0</version> <scope>test</scope> </dependency> <dependency> <groupId>org.scalatest</groupId> <artifactId>scalatest</artifactId> <version>1.2</version> <scope>test</scope> </dependency>
至于
Maybe I should switch to Apache Active MQ. But that sounds less fun.
Am I missing something?
那么,你不要忘记这是测试版吗?确实发生了一些不好的事情,但目前我们正在毫不费力地运行kafka 0.7.