我在尝试运行Mahout中的2newsgroup分类示例时，设置了MAHOUT_LOCAL=true，分类器没有显示混淆矩阵，并且给出了以下警告：
ok. You chose 2 and we'll use naivebayescreating work directory at /tmp/mahout-work-cloudera+ echo 'Preparing 20newsgroups data'Preparing 20newsgroups data+ rm -rf /tmp/mahout-work-cloudera/20news-all+ mkdir /tmp/mahout-work-cloudera/20news-all+ cp -R /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/alt.atheism /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.graphics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.os.ms-windows.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.sys.ibm.pc.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.sys.mac.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/comp.windows.x /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/misc.forsale /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.autos /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.motorcycles /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.sport.baseball /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/rec.sport.hockey /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.crypt /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.electronics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.med /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/sci.space /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/soc.religion.christian /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.guns /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.mideast /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.politics.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-test/talk.religion.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/alt.atheism /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.graphics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.os.ms-windows.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.sys.ibm.pc.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.sys.mac.hardware /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/comp.windows.x /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/misc.forsale /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.autos /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.motorcycles /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.sport.baseball /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/rec.sport.hockey /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.crypt /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.electronics /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.med /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/sci.space /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/soc.religion.christian /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.guns /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.mideast /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.politics.misc /tmp/mahout-work-cloudera/20news-bydate/20news-bydate-train/talk.religion.misc /tmp/mahout-work-cloudera/20news-all+ '[' '' '!=' '' ']'+ echo 'Creating sequence files from 20newsgroups data'Creating sequence files from 20newsgroups data+ ./bin/mahout seqdirectory -i /tmp/mahout-work-cloudera/20news-all -o /tmp/mahout-work-cloudera/20news-seq -owMAHOUT_LOCAL is set, so we don't add HADOOP_CONF_DIR to classpath.MAHOUT_LOCAL is set, running locallyError: Could not find or load main class org.apache.mahout.driver.MahoutDriver请提供任何解决方案，谢谢。
回答：
这个错误是由于Apache Maven路径和POM文件设置不正确引起的。我只是将pom.xml文件（包括mahout-master的完整源代码）放到了apache-maven-3.2.1目录下，然后再次运行命令，这种方法肯定能解决这个问题。
