mavenのサイトaptファイルでドット表記のプロパティを使用するには？

Question

mavenサイトプラグインhttp://maven.apache.org/plugins/maven-site-plugin/examples/creating-content.html#Filteringのドキュメントでは、$contextを使用してドット表記のプロパティにアクセスすることが推奨されています。 私はpomファイルにnexus.urlというプロパティを持っています。 .aptファイルに$context.get("nexus.url")または$context.get("parent.version")を使用すると、解析エラーを与える：-Xフラグを

[ERROR] Error parsing src/site/apt/readme.apt.vm as a velocity template, using as text. 

実行MVNこのトレースを提供します：

java.lang.RuntimeException: Exception when invoking public void org.apache.velocity.tools.generic.SafeConfig.configure(java.util.Map) on org.apache.velocity.tools.view.ViewContextTool@6a950a3b 
at org.apache.velocity.tools.ToolInfo.invoke(ToolInfo.java:375) 
at org.apache.velocity.tools.ToolInfo.configure(ToolInfo.java:294) 
at org.apache.velocity.tools.ToolInfo.create(ToolInfo.java:255) 
at org.apache.velocity.tools.Toolbox.getFromInfo(Toolbox.java:152) 
at org.apache.velocity.tools.Toolbox.get(Toolbox.java:112) 
at org.apache.velocity.tools.ToolContext.findTool(ToolContext.java:221) 
at org.apache.velocity.tools.ToolContext.get(ToolContext.java:206) 
at org.apache.velocity.context.InternalContextAdapterImpl.get(InternalContextAdapterImpl.java:219) 
at org.apache.velocity.runtime.parser.node.ASTReference.getVariableValue(ASTReference.java:740) 
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175) 
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:294) 
at org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:318) 
at org.apache.velocity.Template.merge(Template.java:254) 
at org.apache.velocity.app.VelocityEngine.mergeTemplate(VelocityEngine.java:508) 
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.renderDocument(DefaultSiteRenderer.java:354) 
at org.apache.maven.doxia.siterenderer.DoxiaDocumentRenderer.renderDocument(DoxiaDocumentRenderer.java:51) 
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.renderModule(DefaultSiteRenderer.java:311) 
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render(DefaultSiteRenderer.java:129) 
at org.apache.maven.plugins.site.render.SiteMojo.renderDoxiaDocuments(SiteMojo.java:261) 
at org.apache.maven.plugins.site.render.SiteMojo.renderLocale(SiteMojo.java:172) 
at org.apache.maven.plugins.site.render.SiteMojo.execute(SiteMojo.java:141) 
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:133) 
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208) 
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) 
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) 
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:108) 
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:76) 
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) 
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:116) 
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:361) 
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:155) 
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:584) 
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:213) 
at org.apache.maven.cli.MavenCli.main(MavenCli.java:157) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:497) 
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) 
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) 
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) 
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) 

Caused by: java.lang.NullPointerException 
at org.apache.velocity.tools.view.ViewContextTool.configure(ViewContextTool.java:69) 
at org.apache.velocity.tools.generic.SafeConfig.configure(SafeConfig.java:113) 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:497) 
at org.apache.velocity.tools.ToolInfo.invoke(ToolInfo.java:363) 

Answer 1

はそれを考え出しました。 maven-site-pluginのバージョン3.5.1でうまく動作します。