Linux Hadoop: ?ERROR : JAVA_HOME 未设置？

Hadoop: ?ERROR : JAVA_HOME is not set?

提问by koukou

I'm trying to install Hadoop on Ubuntu 11.10. I set the JAVA_HOMEvariable in the file conf/hadoop-env.shto:

我正在尝试在 Ubuntu 11.10 上安装 Hadoop。我将JAVA_HOME文件中的变量设置conf/hadoop-env.sh为：

# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

and then I execute these commands (Standalone Operation):

然后我执行这些命令（独立操作）：

$ 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:

但是在执行第三个命令时出现以下错误：

ERROR : JAVA_HOME is not set

错误：未设置 JAVA_HOME

Is the JAVA_HOMEvariable not set correctly?

是JAVA_HOME不正确的变量？

回答by alain.janinm

Type echo $JAVA_HOMEin your terminal to be sure your JAVA_HOMEis set.

输入echo $JAVA_HOME您的终端，以确保您的JAVA_HOME设置。

You can also type java -versionto know what version of java you are actually using.

您还可以键入java -version以了解您实际使用的 Java 版本。

By the way, reading your description it seems your actually writing

顺便说一句，阅读您的描述似乎您实际上是在写作

export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

in the file conf/hadoop-env.sh, you should write it in your terminal or in ~/.bashrcor ~/.profilethen type source < path to modified file >.

在文件中conf/hadoop-env.sh，您应该将其写入终端或输入~/.bashrc或~/.profile输入source < path to modified file >.

回答by user1489515

Make sure that you have removed the comment tag and changed your JAVA_HOMEin the hadoop-env.shas well as the appropriate .bashrcand/or .profile:

确保您已删除评论标签并更改您的JAVA_HOMEinhadoop-env.sh以及适当的.bashrc和/或.profile：

# export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

should be

应该

export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk

You can set your JAVA_HOMEand PATHfor all users (make sure you haven't previously set this to the wrong path) in /etc/profile.

您可以设置JAVA_HOME并PATH为所有用户（请确保您之前没有将其设置为错误的路径）/etc/profile。

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

另外，不要忘记通过注销/登录或执行来激活新的更改source /etc/profile。

回答by nantitv

You should set JAVA_HOMEin the hadoop-env.shfile also which is in the Hadoop configuration directory. By default the JAVA_HOMEsetting line is commented.

您还应该JAVA_HOME在hadoop-env.shHadoop 配置目录中的文件中进行设置。默认情况下，JAVA_HOME设置行是注释的。

回答by Arun Krishnan Cp

• hadoop ERROR : JAVA_HOME is not set

• hadoop 错误：未设置 JAVA_HOME

Above error is because of the space in between two words.

以上错误是因为两个单词之间的空格。

Eg: Java located in C:\Program Files\Java--> Space in between Programand fileswould cause the above problem. If you remove the space, it would not show any error.

例如：Java 位于 C:\Program Files\Java--> Program和files之间的空间会导致上述问题。如果删除空格，则不会显示任何错误。

回答by Paulo Fidalgo

You can add in your .bashrcfile:

您可以在.bashrc文件中添加：

export JAVA_HOME=$(readlink -f /usr/bin/java | sed "s:bin/java::")

and it will dynamically change when you update your packages.

它会在您更新软件包时动态更改。

回答by American curl

Copy this export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdkto hadoop-env.shfile.

将此复制export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk到hadoop-env.sh文件中。

JAVA_HOMEis the location where java binaries are present.

JAVA_HOME是 java 二进制文件所在的位置。

回答by Ajak6

I tried the above solutions but the following worked on me

我尝试了上述解决方案，但以下对我有用

export JAVA_HOME=/usr/java/default

回答by Muthukrishnan

The solution that worked for me was setting my JAVA_HOMEin /etc/environment

对我有用的解决方案是设置我JAVA_HOME的/etc/environment

Though JAVA_HOMEcan be set inside the /etc/profile files, the preferred location for JAVA_HOMEor any system variable is /etc/environment.

虽然JAVA_HOME可以在 /etc/profile 文件中设置，但JAVA_HOME或任何系统变量的首选位置是/etc/environment.

Open /etc/environment in any text editor like nano or vim and add the following line:

在任何文本编辑器（如 nano 或 vim）中打开 /etc/environment 并添加以下行：

JAVA_HOME="/usr/lib/jvm/your_java_directory"

Load the variables:

加载变量：

source /etc/environment

Check if the variable loaded correctly:

检查变量是否正确加载：

echo $JAVA_HOME

回答by Santonio

I solved this in my env, without modify hadoop-env.sh

我在我的环境中解决了这个问题，没有修改 hadoop-env.sh

You'd be better using /bin/bashas default shell not /bin/sh

你最好不要使用/bin/bash默认 shell/bin/sh

Check these before:

之前检查这些：

1. You have already config java and env (success echo $JAVA_HOME)
2. right config hadoop

1. 您已经配置了 java 和 env（成功echo $JAVA_HOME）
2. 正确配置hadoop

echo $SHELLin every node, check if print /bin/bashif not, vi /etc/passwd, add /bin/bashat tail of your username ref

echo $SHELL在每个节点中，检查是否打印，/bin/bash如果没有，在用户名 ref 的尾部vi /etc/passwd添加/bin/bash

Changing default shell in Linux

https://blog.csdn.net/whitehack/article/details/51705889

更改 Linux 中的默认 shell

https://blog.csdn.net/whitehack/article/details/51705889

回答by nickc

In some distributives(CentOS/OpenSuSe,...) will work only if you set JAVA_HOME in the /etc/environment.

在某些发行版（CentOS/OpenSuSe，...）中，仅当您在 /etc/environment 中设置 JAVA_HOME 时才有效。