自定义Nifi处理器抛出构建错误：Nifi nar maven插件的空指针异常

Question

我试图建立自定义的nifi处理器与控制器服务，我已配置项目设置，以建立nar文件，而建立得到以下错误，这看起来是从nifi库，plz让我知道有任何解决方案或变通办法退出。这看起来是nif-nar-maven-plugin问题，可能是版本的问题！！

[INFO] Generating documentation for NiFi extensions in the NAR... [INFO] Found a dependency on version 1.11.4 of NiFi API
[ERROR] Could not generate extensions' documentation
org.apache.maven.plugin.MojoExecutionException: Failed to create Extension Documentation
at org.apache.nifi.NarMojo.generateDocumentation (NarMojo.java:596)
at org.apache.nifi.NarMojo.execute (NarMojo.java:499)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:567)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
Caused by: java.lang.NullPointerException
at org.apache.nifi.NarMojo.getRequiredServiceDefinitions (NarMojo.java:708)
at org.apache.nifi.NarMojo.writeDocumentation (NarMojo.java:634)
at org.apache.nifi.NarMojo.writeDocumentation (NarMojo.java:605)
at org.apache.nifi.NarMojo.generateDocumentation (NarMojo.java:577)
at org.apache.nifi.NarMojo.execute (NarMojo.java:499)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:567)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:282)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:225)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:406)
at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary for custom-processor 1.0-SNAPSHOT:
[INFO]
[INFO] custom-processor ................................... SUCCESS [ 6.729 s]
[INFO] nifi-sample-api .................................... SUCCESS [ 4.566 s]
[INFO] nifi-sample ........................................ SUCCESS [ 12.118 s]
[INFO] nifi-custom-processors ............................. SUCCESS [ 10.350 s]
[INFO] nifi-custom-nar .................................... FAILURE [ 4.535 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 44.067 s
[INFO] Finished at: 2020-04-06T22:23:28+05:30
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.nifi:nifi-nar-maven-plugin:1.3.1:nar (default-nar) on project nifi-custom-nar: Failed to create Extension Documentation: NullPointerException -> [Help

Answer 1

您应该在nar子项目的pom文件中添加以下依赖项。

    <dependency>
        <groupId>org.apache.nifi</groupId>
        <artifactId>nifi-standard-services-api-nar</artifactId>
        <version>1.11.4</version>
        <type>nar</type>
    </dependency>