Hadoop：«错误：未设置JAVA_HOME» [英] Hadoop: «ERROR : JAVA_HOME is not set»

问题描述

我试图在Ubuntu 11.10上安装Hadoop。我将文件 conf / hadoop-env.sh 中的 JAVA_HOME 变量设置为：

 ＃export JAVA_HOME = / usr / lib / jvm / java-1.6.0 -b openjdk 
   
 $ b 
然后我执行这些命令（独立操作）：
 
 
  $ mkdir输入
 $ cp conf / *。xml输入
 $ bin / hadoop jar hadoop-examples  -  *。jar grep输入输出'dfs [az。] +'
 $ cat output / * 
  
但执行第三个命令时出现以下错误： 
 
 
 
 
错误：未设置JAVA_HOME  
  JAVA_HOME 变量设置不正确？
解决方案
确保您已经删除了评论标签并更改了您的 JAVA_HOME 在 hadoop-env.sh 以及相应的 .bashrc 和/或 .profile ： 
 
 
 ＃export JAVA_HOME = / usr / lib中/ J vm / java-1.6.0-openjdk 
  
应该是
 
 
  export JAVA_HOME = / usr / lib / jvm / java-1.6.0 -openjdk 
  
您可以为所有用户设置您的 JAVA_HOME 和 PATH 在 / etc / profile 中。
 
 
 
另外，不要将它设置为错误的路径忘记通过注销/ in或通过执行 source / etc / profile 激活新更改。
 
I'm trying to install Hadoop on Ubuntu 11.10. I set the JAVA_HOME variable in the file conf/hadoop-env.sh to: 
# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk
and then I execute these commands (Standalone Operation):
$ mkdir input 
$ cp conf/*.xml input 
$ bin/hadoop jar hadoop-examples-*.jar grep input output 'dfs[a-z.]+' 
$ cat output/*
but I have the following error when executing the third command:

  
ERROR : JAVA_HOME is not set
Is the JAVA_HOME variable not set correctly?
解决方案
Make sure that you have removed the comment tag and changed your JAVA_HOME in the hadoop-env.sh as well as the appropriate .bashrc and/or .profile:
# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk
should be
export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk
You can set your JAVA_HOME and PATH for all users (make sure you haven't previously set this to the wrong path) in /etc/profile.

Also, don't forget to activate the new change by logging-out/in or by executing source /etc/profile.

                        
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