基于源码启动Kafka Connector遇类加载错误求助

错误分析 #

你遇到的ReflectionsException本质是Kafka Connect在扫描插件类时，尝试加载org.eclipse.swt.events.ControlListener类但找不到。SWT是桌面UI开发库，完全不属于Kafka Connector的核心依赖范畴，说明你的项目环境混入了无关的SWT依赖或JAR文件，干扰了类扫描流程。

解决步骤 #

• 移除无关依赖：检查项目构建文件（Maven的pom.xml或Gradle的build.gradle），直接删除所有org.eclipse.swt开头的依赖项。
• 清理插件目录：如果配置了plugin.path参数，检查该目录下是否存在包含SWT类的JAR，将这些无关JAR移出。
• 排除传递依赖：如果是其他依赖间接引入了SWT，在构建配置中排除这个传递依赖：
  Maven配置示例：

  <dependency>
      <groupId>xxx</groupId>
      <artifactId>xxx</artifactId>
      <version>xxx</version>
      <exclusions>
          <exclusion>
              <groupId>org.eclipse.swt</groupId>
              <artifactId>*</artifactId>
          </exclusion>
      </exclusions>
  </dependency>
  

  Gradle配置示例：

  implementation('xxx:xxx:xxx') {
      exclude group: 'org.eclipse.swt'
  }
  

• 临时容错方案（仅应急）：如果暂时无法清理依赖，可添加JVM启动参数-Dorg.reflections.skipClassNotFound=true跳过类找不到的错误，但这只是临时规避，建议优先清理依赖。

原始报错信息 #

[2023-09-12 17:04:22,050] INFO Scanning for plugin classes. This might take a moment ... (org.apache.kafka.connect.cli.ConnectStandalone)
[2023-09-12 17:04:24,566] INFO Reflections took 2369 ms to scan 85 urls, producing 7787 keys and 30651 values [using 8 cores] (org.reflections.Reflections)
[2023-09-12 17:04:24,584] WARN could not get type for name org.eclipse.swt.events.ControlListener from any class loader (org.reflections.Reflections)
org.reflections.ReflectionsException: could not get type for name org.eclipse.swt.events.ControlListener
    at org.reflections.ReflectionUtils.forName(ReflectionUtils.java:312)
    at org.reflections.Reflections.expandSuperTypes(Reflections.java:382)
    at org.reflections.Reflections.<init>(Reflections.java:140)
    at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader$InternalReflections.<init>(DelegatingClassLoader.java:490)
    at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.scanPluginPath(DelegatingClassLoader.java:363)
    at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.scanUrlsAndAddPlugins(DelegatingClassLoader.java:298)
    at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.initPluginLoader(DelegatingClassLoader.java:248)
    at org.apache.kafka.connect.runtime.isolation.DelegatingClassLoader.initLoaders(DelegatingClassLoader.java:241)
    at org.apache.kafka.connect.runtime.isolation.Plugins.<init>(Plugins.java:60)
    at org.apache.kafka.connect.cli.ConnectStandalone.main(ConnectStandalone.java:78)

内容的提问来源于stack exchange，提问作者Red256