Kafka Connect 找不到开发插件的类

Question

我为实现 SinkConnector 的 kafka connect 创建了一个插件，我使用 gradle jar 任务将它打包到一个 jar 中：

jar {
  archiveName='name.jar'
}

我将它复制到 kafka 集群中的一个文件夹中，并设置 CLASSPATH=我的 jar 所在的位置。 然后我执行 kafka 脚本来启动独立连接，它给了我一个错误，说找不到我的类：

[2017-07-25 05:15:52,084] WARN could not get type for name mypackage.SplunkSinkConnector from any class loader (org.reflections.Reflections:384)
org.reflections.ReflectionsException: could not get type for name mypackage.SplunkSinkConnector
        at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:378)
        at org.reflections.ReflectionUtils.forNames(ReflectionUtils.java:397)
        at org.reflections.Reflections.getSubTypesOf(Reflections.java:367)
        at org.apache.kafka.connect.runtime.PluginDiscovery.connectorPlugins(PluginDiscovery.java:76)
        at org.apache.kafka.connect.runtime.PluginDiscovery.scanClasspathForPlugins(PluginDiscovery.java:70)
        at org.apache.kafka.connect.runtime.AbstractHerder$1.run(AbstractHerder.java:354)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassNotFoundException: mypackage.SplunkSinkConnector
        at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:376)
        ... 6 more
[2017-07-25 05:15:52,419] INFO Reflections took 1586 ms to scan 62 urls, producing 3002 keys and 15379 values  (org.reflections.Reflections:229)
[2017-07-25 05:15:52,420] WARN could not get type for name mypackage.SplunkSinkConnector from any class loader (org.reflections.Reflections:384)
org.reflections.ReflectionsException: could not get type for name mypackage.SplunkSinkConnector
        at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:378)
        at org.reflections.ReflectionUtils.forNames(ReflectionUtils.java:397)
        at org.reflections.Reflections.getSubTypesOf(Reflections.java:367)
        at org.apache.kafka.connect.runtime.ConnectorFactory.getConnectorClass(ConnectorFactory.java:69)
        at org.apache.kafka.connect.runtime.ConnectorFactory.newConnector(ConnectorFactory.java:38)
        at org.apache.kafka.connect.runtime.AbstractHerder.getConnector(AbstractHerder.java:334)
        at org.apache.kafka.connect.runtime.AbstractHerder.validateConnectorConfig(AbstractHerder.java:233)
        at org.apache.kafka.connect.runtime.standalone.StandaloneHerder.putConnectorConfig(StandaloneHerder.java:159)
        at org.apache.kafka.connect.cli.ConnectStandalone.main(ConnectStandalone.java:93)
Caused by: java.lang.ClassNotFoundException: mypackage.SplunkSinkConnector
        at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:376)
        ... 8 more

知道为什么不拿起我的罐子吗？

谢谢

=================================

编辑：Kakfa Connect 版本 10.2.1，根据脚本，类路径计算为：CLASSPATH="$CLASSPATH":"$KAFKA_HOME/libs/*"

Answer 1

您能否检查您的 .jar 文件以确保该类存在。使用 Scala 作为 JVM shell：

// Or Maybe try $CLASSPATH with the full classpath that you are using.
scala -classpath path-to-jar.jar
// If class is not loaded, this will trigger an error.
classOf[mypackage.SplunkSinkConnector]

仅供参考，我正在这样做，使用自定义 .jar 插件和通过 CLASSPATH 环境变量加载的 Kafka Connect。

更新：这是我的插件的build.gradle 文件。 IMO，这是构建具有一些简单依赖项的 Java .jar 的最简单方法。我用gradle jar 构建jar，它将在./build/libs/(project-name).jar 创建：

apply plugin: 'java'
apply plugin: 'idea'

sourceCompatibility = 1.8

repositories {
    mavenLocal()
    mavenCentral()
    maven { url "http://packages.confluent.io/maven/" }
}

configurations {
    all*.exclude group: 'org.slf4j', module: 'slf4j-log4j12'
    all*.exclude group: 'log4j'
}

dependencies {
    compile 'io.confluent:kafka-connect-storage-partitioner:3.2.1'
    compile 'org.apache.kafka:connect-api:0.10.2.1'

    testCompile 'junit:junit:4.+'
}

idea {
    project {
        languageLevel = '1.8'
    }
}