java - mahout - 运行 grouplens 示例错误

Question

我在尝试按照 https://cwiki.apache.org/MAHOUT/recommendationexamples.html 上的教程运行 grouplens 示例时遇到错误

我的参数:

    windows 7 32bit,
    jdk 1.7
    maven 3.0.5
    svn checkout of http://svn.apache.org/repos/asf/mahout/trunk
    mahout v.0.8
    installation: mvn -DskipTest clean install

我的猜测是我需要安装 cygwin，但在有人确认这一点之前我不想搞砸。

错误:

mvn -e -q exec:java -Dexec.mainClass="org.apache.mahout.cf.taste.example.grouplens.GroupLe
nsRecommenderEvaluatorRunner" -Dexec.args="-i ratings.dat"
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project mahout: An exception occured while executing the Java class. org.apache.mahout.cf.
taste.example.grouplens.GroupLensRecommenderEvaluatorRunner -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project mahout: An exception occured while
 executing the Java class. org.apache.mahout.cf.taste.example.grouplens.GroupLensRecommenderEvaluatorRunner
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:217)
        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:84)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
        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:601)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.MojoExecutionException: An exception occured while executing the Java class. org.apache.mahout.cf.taste.example.grouplens.GroupLensRecommenderEvaluato
rRunner
        at org.codehaus.mojo.exec.ExecJavaMojo.execute(ExecJavaMojo.java:352)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
        ... 19 more
Caused by: java.lang.ClassNotFoundException: org.apache.mahout.cf.taste.example.grouplens.GroupLensRecommenderEvaluatorRunner
        at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
        at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:285)
        at java.lang.Thread.run(Thread.java:722)
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

Answer 1

我通过首先正确安装 hadoop 解决了这个问题，然后使用 *all.sh 启动脚本启动 hadoop 实例。

之后我安装了 mahout，cd Examples/ 并运行了 abouve 命令，它起作用了。