我是hadoop新手，我正在尝试在我最近安装在桌面上的单节点集群上运行字数计算作业。我遵循以下教程：
http://javabeginnerstutorial.com/hadoop/your-first-hadoop-map-reduce-job/
目前，我被困在步骤3，并收到一个错误，当我试图运行：
~/development/hadoop\u projects/word\u count$mvn clean安装
我得到的错误是：
错误：未正确定义java\u home。我们不能执行usr/lib/jvm/java-7-openjdk-amd64/bin/java
我想我安装maven是正确的，但不知道。我在ubuntu14.04上运行这个程序，有没有关于java主路径的想法，或者这里还有其他问题？

上面的错误是通过修复java\u home路径修复的，但是现在我在运行mvn clean install时遇到以下错误：

hduser@venus:~/development/Hadoop_projects/word_count$ mvn clean install
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.088s
[INFO] Finished at: Tue Jul 14 23:07:21 PDT 2015
[INFO] Final Memory: 5M/240M
[INFO] ------------------------------------------------------------------------
[ERROR] The goal you specified requires a project to execute but there is no POM in this directory (/home/hduser/development/Hadoop_projects/word_count). Please verify you invoked Maven from the correct directory. -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[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/MissingProjectException

我在word\u count文件夹中创建了pom.xml文件，但由于某些原因，在运行mvn时无法识别它。当我 ls word_count 目录中没有pom.xml，但我可以在文件gui窗口中看到它。