blocks|key|151694|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|151695|find+/usr/lib/jvm/java-1.x.x-openjdk|ordered-list-item|offset|length|style|CODE|151696|vim+/etc/profile|151697|151698|如果以非特权用户身份登录，请准备sudo。sudo+vim|151699|Press+'i‘进入插入模式|unordered-list-item|151700|
|151701|add：|151702|151703|导出您找到的路径导出PATH=$JAVA_HOME/bin:$PATH|151704|logout并重新登录、重新启动或使用source+/etc/profile在当前JAVA_HOME=|151705|
中立即应用更改|151706|entityMap^0|0|0|10|0|0|G|0|0|L|8|0|0|0|0|0|0|J|J|0|0^^$0|@$1|2|3|-4|4|5|6|12|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|13|7|@$D|14|E|15|F|G]]|8|@]|9|$]]|$1|H|3|I|4|C|6|16|7|@$D|17|E|18|F|G]]|8|@]|9|$]]|$1|J|3|-4|4|5|6|19|7|@]|8|@]|9|$]]|$1|K|3|L|4|5|6|1A|7|@$D|1B|E|1C|F|G]]|8|@]|9|$]]|$1|M|3|N|4|O|6|1D|7|@]|8|@]|9|$]]|$1|P|3|Q|4|5|6|1E|7|@]|8|@]|9|$]]|$1|R|3|S|4|O|6|1F|7|@]|8|@]|9|$]]|$1|T|3|-4|4|5|6|1G|7|@]|8|@]|9|$]]|$1|U|3|V|4|5|6|1H|7|@]|8|@]|9|$]]|$1|W|3|X|4|O|6|1I|7|@$D|1J|E|1K|F|G]]|8|@]|9|$]]|$1|Y|3|Z|4|5|6|1L|7|@]|8|@]|9|$]]|$1|10|3|-4|4|5|6|1M|7|@]|8|@]|9|$]]]|11|$]]

<ol>
<li><code>find /usr/lib/jvm/java-1.x.x-openjdk</code></li>
<li><code>vim /etc/profile</code>

Prepend sudo if logged in as not-privileged user, ie. <code>sudo vim</code></li>
<li>Press 'i' to get in insert mode</li>
<li>add:

<pre><code>export JAVA_HOME="path that you found"

export PATH=$JAVA_HOME/bin:$PATH
</code></pre></li>
<li>logout and login again, reboot, or use <code>source /etc/profile</code> to apply changes immediately in your current shell</li>
</ol>

blocks|key|154507|text|对于所有用户，我建议在/etc/profile.d/java_home.sh中创建以下代码行的文件|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|154508|#+Set+JDK+installation+directory+according+to+selected+Java+compiler

export+JAVA_HOME=$(readlink+-f+/usr/bin/javac+%7C+sed+"s:/bin/javac::")|code-block|syntax|javascript|154509|这将动态更新，并与替代系统很好地协同工作。但请注意，更新只会在新的登录shell中进行。|154510|entityMap^0|B|R|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

For all users, I would recommend creating a file in <code>/etc/profile.d/java_home.sh</code> the following lines
<pre><code># Set JDK installation directory according to selected Java compiler

export JAVA_HOME=$(readlink -f /usr/bin/javac | sed &quot;s:/bin/javac::&quot;)
</code></pre>
This will update dynamically and works well with the alternatives system. Do note though that the update will only take place in a new login shell.

blocks|key|151689|text|您可以使用/etc/profile或更好的文件，如/etc/profile.d/jdk_home.sh|type|unstyled|depth|inlineStyleRanges|entityRanges|data|151690|export+JAVA_HOME=/usr/java/jdk1.7.0_05/|code-block|syntax|javascript|151691|您必须记住，此文件仅与新的登录shell一起加载。因此，在bash或新的gnome-+-l之后，它不会随着新的Java版本而改变。|151692|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You could use /etc/profile or better a file like /etc/profile.d/jdk_home.sh

<pre><code>export JAVA_HOME=/usr/java/jdk1.7.0_05/
</code></pre>

You have to remember that this file is only loaded with new login shells.. So after bash -l or a new gnome-session and that it doesn't change with new Java versions.

blocks|key|150498|text|对于我来说，在RHEL7中没有其他答案是“坚持”的，即使是直接在/etc/profile或~/.bash_profile中设置JAVA_HOME和PATH也不会起作用。每次我尝试检查是否设置了JAVA_HOME时，结果都是空白的：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|150499|$+echo+$JAVA_HOME
++++(<--+no+output)|code-block|syntax|javascript|150500|我要做的是在/etc/profile.d/jdk_home.sh中设置一个脚本|150501|#!/bin/sh
export+JAVA_HOME=/opt/ibm/java-x86_64-60/
export+PATH=$JAVA_HOME/bin:$PATH|150502|我最初忽略了第一行(+#!/bin/sh)，没有它就不能工作。|150503|现在它起作用了：|150504|$+echo+$JAVA_HOME
/opt/ibm/java-x86_64-60/|150505|entityMap^0|W|C|19|F|1R|9|21|4|2O|9|0|0|6|Q|0|0|B|9|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|17|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|1B|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1C|8|@$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1F|8|@]|D|@]|E|$]]|$1|S|3|T|5|H|7|1G|8|@]|D|@]|E|$I|J]]|$1|U|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]]|V|$]]

None of the other answers were "sticking" for me in RHEL 7, even setting <code>JAVA_HOME</code> and <code>PATH</code> directly in <code>/etc/profile</code> or <code>~/.bash_profile</code> would not work. Each time I tried to check if <code>JAVA_HOME</code> was set, it would come up blank:

<pre><code>$ echo $JAVA_HOME
 (&lt;-- no output)
</code></pre>

What I had to do was set up a script in <code>/etc/profile.d/jdk_home.sh</code>:

<pre><code>#!/bin/sh
export JAVA_HOME=/opt/ibm/java-x86_64-60/
export PATH=$JAVA_HOME/bin:$PATH
</code></pre>

I initially neglected the first line (the <code>#!/bin/sh</code>), and it won't work without it.

Now it's working:

<pre><code>$ echo $JAVA_HOME
/opt/ibm/java-x86_64-60/
</code></pre>

blocks|key|154608|text|sudo+gedit+.bashrc类型的|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|154609|开放终端|ordered-list-item|154610|154611|154612|它会询问你的密码。键入密码后，它将打开bash文件。然后转到end并键入：|154613|154614|导出JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64/“导出PATH=$PATH:$JAVA_HOME/bin|154615|然后|154616|保存该文件并从文件|154617|中退出|154618|以上是针对单个用户的。对于所有用户，您必须执行以下步骤|154619|154620|gedit+/etc/profile|154621|154622|154623|export+JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64/"|154624|154625|154626|export+PATH=$PATH:$JAVA_HOME/bin|154627|154628|entityMap^0|0|I|0|0|0|0|0|0|0|0|0|0|0|0|0|I|0|0|0|0|1H|0|0|0|0|W|0|0^^$0|@$1|2|3|4|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|1E|8|@]|D|@]|E|$]]|$1|I|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]|$1|K|3|L|5|H|7|1H|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]|$1|N|3|O|5|6|7|1J|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1K|8|@]|D|@]|E|$]]|$1|R|3|S|5|H|7|1L|8|@]|D|@]|E|$]]|$1|T|3|U|5|6|7|1M|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1N|8|@]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]|$1|Y|3|Z|5|H|7|1P|8|@$9|1Q|A|1R|B|C]]|D|@]|E|$]]|$1|10|3|-4|5|6|7|1S|8|@]|D|@]|E|$]]|$1|11|3|-4|5|6|7|1T|8|@]|D|@]|E|$]]|$1|12|3|13|5|H|7|1U|8|@$9|1V|A|1W|B|C]]|D|@]|E|$]]|$1|14|3|-4|5|6|7|1X|8|@]|D|@]|E|$]]|$1|15|3|-4|5|6|7|1Y|8|@]|D|@]|E|$]]|$1|16|3|17|5|H|7|1Z|8|@$9|20|A|21|B|C]]|D|@]|E|$]]|$1|18|3|-4|5|6|7|22|8|@]|D|@]|E|$]]|$1|19|3|-4|5|6|7|23|8|@]|D|@]|E|$]]]|1A|$]]

<ol>
<li>Open terminal and type <code>sudo gedit .bashrc</code>
</li>
<li>It will ask you your password. After typing the password, it will open the bash file. Then go to end and type:
<pre><code>export JAVA_HOME=&quot;/usr/lib/jvm/java-8-openjdk-amd64/&quot;
export PATH=$PATH:$JAVA_HOME/bin
</code></pre>
</li>
<li>Then save the file and exit from file
</li>
</ol>
Above is for a single user. For all users, you have to follow below steps
<ol>
<li><code>gedit /etc/profile</code>
</li>
<li><code>export JAVA_HOME=&quot;/usr/lib/jvm/java-8-openjdk-amd64/&quot;</code>
</li>
<li><code>export PATH=$PATH:$JAVA_HOME/bin</code>
</li>
</ol>

blocks|key|2948684|text|复制您安装的bin文件路径|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2948685|YOUR+PATH|code-block|syntax|javascript|2948686|通过键入以下命令打开终端并编辑环境文件。|2948687|sudo+nano+/etc/environment|2948688|在此文件中，添加以下行(将YOUR_PATH替换为刚刚复制的路径)：|offset|length|style|CODE|2948689|JAVA_HOME="YOUR_PATH"|2948690|这应该足以设置环境变量。现在重新加载此文件：|2948691|source+/etc/environment|2948692|现在通过执行以下命令来测试它：|2948693|echo+$JAVA_HOME|2948694|entityMap^0|0|0|0|0|D|9|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|16|8|@$M|17|N|18|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|10|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|11|$]]

Copy the bin file path you installed

<pre><code>YOUR PATH
</code></pre>

open terminal and edit environment file by typing following command,

<pre><code>sudo nano /etc/environment
</code></pre>

In this file, add the following line (replacing <code>YOUR_PATH</code> by the just copied path):

<pre><code>JAVA_HOME="YOUR_PATH"
</code></pre>

That should be enough to set the environment variable. Now reload this file:

<pre><code>source /etc/environment
</code></pre>

now test it by executing:

<pre><code>echo $JAVA_HOME
</code></pre>

blocks|key|153183|text|做Oracle做的事情(作为Sun的一名前雇员，我无法适应这一点)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|153184|ln+-s+latestJavaRelease+/usr/java/default|153185|其中，latestJavaRelease是要使用的版本|153186|然后导出JAVA_HOME=/usr/java/default|153187|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Doing what Oracle does (as a former Sun Employee I can't get used to that one)

ln -s latestJavaRelease /usr/java/default 
Where latestJavaRelease is the version that you want to use

then export JAVA_HOME=/usr/java/default

blocks|key|150632|text|答案是之前的帖子是有效的。但在以下方面，没有一个答案是完整的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|150633|由于某些原因(如/etc/profile):中所述)，不建议|150634|更改/etc/profile|ordered-list-item|150635|150636|150637|blockquote|150638|150639|150640|除非您知道自己在做什么，否则更改此文件不是一个好主意。最好在/etc/profile.d/中创建一个custom.sh外壳脚本来对您的环境进行自定义更改，因为这将避免在将来的更新中进行合并。*|unordered-list-item|150641|150642|因此如上所述，为自定义changes.|150643|Now，创建/etc/profile.d/.sh文件，以便始终使用正在安装的较新版本的|150644|进行更新，千万不要放入绝对路径，而应使用：|150645|150646|150647|150648|+#如果把jdk作为java的家|150649|150650|导出JAVA_HOME=$(readlink+-f+/usr/bin/javac+%7C+sed+"s:/bin/javac::")|150651|或|150652|#如果将jre作为java+home|150653|导出JAVA_HOME=$(readlink+-f+/usr/bin/java+%7C+sed+"s:/bin/java::")|150654|150655|150656|并记住将#！/bin/bash放在custom.sh文件|offset|length|style|BOLD|150657|上|150658|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|4|B|0|0^^$0|@$1|2|3|4|5|6|7|1M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1O|8|@]|9|@]|A|$]]|$1|G|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|I|3|-4|5|J|7|1R|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|1S|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|1U|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|1V|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1W|8|@]|9|@]|A|$]]|$1|S|3|T|5|O|7|1X|8|@]|9|@]|A|$]]|$1|U|3|V|5|F|7|1Y|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1Z|8|@]|9|@]|A|$]]|$1|X|3|-4|5|6|7|20|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|21|8|@]|9|@]|A|$]]|$1|Z|3|10|5|J|7|22|8|@]|9|@]|A|$]]|$1|11|3|-4|5|6|7|23|8|@]|9|@]|A|$]]|$1|12|3|13|5|6|7|24|8|@]|9|@]|A|$]]|$1|14|3|15|5|6|7|25|8|@]|9|@]|A|$]]|$1|16|3|17|5|6|7|26|8|@]|9|@]|A|$]]|$1|18|3|19|5|6|7|27|8|@]|9|@]|A|$]]|$1|1A|3|-4|5|6|7|28|8|@]|9|@]|A|$]]|$1|1B|3|-4|5|6|7|29|8|@]|9|@]|A|$]]|$1|1C|3|1D|5|F|7|2A|8|@$1E|2B|1F|2C|1G|1H]]|9|@]|A|$]]|$1|1I|3|1J|5|6|7|2D|8|@]|9|@]|A|$]]|$1|1K|3|-4|5|6|7|2E|8|@]|9|@]|A|$]]]|1L|$]]

The answer is given previous posts is valid. But not one answer is complete with respect to: 

<ol>
<li>Changing the /etc/profile is not recommended simply because of the reason (as stated in /etc/profile):</li>
</ol>

<blockquote>
 <ul>
 <li>It's NOT a good idea to change this file unless you know what you are doing. It's much better to create a custom.sh shell script in
 /etc/profile.d/ to make custom changes to your environment, as this
 will prevent the need for merging in future updates.*</li>
 </ul>
</blockquote>

<ol start="2">
<li>So as stated above create /etc/profile.d/custom.sh file for custom changes.</li>
<li>Now, to always keep updated with newer versions of Java being installed, never put the absolute path, instead use:</li>
</ol>

<blockquote>
 #if making jdk as java home
 
 export JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:/bin/javac::")
 
 OR
 
 #if making jre as java home
 
 export JAVA_HOME=$(readlink -f /usr/bin/java | sed "s:/bin/java::")
</blockquote>

<ol start="4">
<li>And remember to have #! /bin/bash on the custom.sh file</li>
</ol>

blocks|key|2949016|text|首先，您需要找出您的PC中安装了哪种Java以及要使用哪种Java。用于具有root权限的开放终端。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2949017|+sudo+su

+ls+/usr/lib/jvm/|code-block|syntax|javascript|2949018|现在，它将列出可用的java版本。选择列出的版本。|2949019|将路径复制到那里。|2949020|现在打开bashrc|2949021|++nano+~/.bashrc|2949022|在末尾添加以下命令|2949023|+export+JAVA_HOME="path+that+you+copied"

++export+PATH=$JAVA_HOME/bin:$PATH|2949024|之后，保存文件，然后按Ctrl%2BS，然后按Ctrl%2BX退出|2949025|现在运行以下命令：|2949026|++source+~/.bashrc|2949027|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|19|8|@]|9|@]|A|$]]|$1|W|3|X|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

First you need to find out which Java is installed in your PC and which one to use.
For that open terminal with root permission.
<pre><code> sudo su

 ls /usr/lib/jvm/
</code></pre>
Now it will list the available java versions.
Select the listed version.
Copy the path till there.
Now open bashrc
<pre><code> nano ~/.bashrc
</code></pre>
add the following commands to the end
<pre><code> export JAVA_HOME=&quot;path that you copied&quot;

 export PATH=$JAVA_HOME/bin:$PATH
</code></pre>
after that save the file and exit by pressing Ctrl+S followed by Ctrl+X
Now run the below command:
<pre><code> source ~/.bashrc
</code></pre>

blocks|key|154637|text|这是一个非常简单的解决问题的脚本|type|unstyled|depth|inlineStyleRanges|entityRanges|data|154638|export+JAVA_HOME_BIN=`which+java`
export+JAVA_HOME_DIR=`dirname+$JAVA_HOME_BIN`
export+JAVA_HOME=`dirname+$JAVA_HOME_DIR`|code-block|syntax|javascript|154639|对于测试：|154640|echo+$JAVA_HOME|154641|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This is a very simple script to solve the problem

<pre><code>export JAVA_HOME_BIN=`which java`
export JAVA_HOME_DIR=`dirname $JAVA_HOME_BIN`
export JAVA_HOME=`dirname $JAVA_HOME_DIR`
</code></pre>

And for testing:

<pre><code>echo $JAVA_HOME
</code></pre>

blocks|key|150699|text|使用1...Using快捷键Ctlr+%2B+Alt+%2B+T打开终端|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|150700|对以下命令执行2...Execute命令：|150701|echo+export+JAVA_HOME='$(readlink+-f+/usr/bin/javac+%7C+sed+"s:/bin/javac::")'+%7C+sudo+tee+/etc/profile.d/jdk_home.sh+>+/dev/null|code-block|syntax|javascript|150702|3...(建议)重新启动您的VM+/计算机。如果不想重新启动计算机，可以使用source+/etc/source|150703|使用4...Using快捷键Ctlr+%2B+Alt+%2B+T打开终端|150704|带有的5...Verified+JAVA_HOME安装包|150705|echo+$JAVA_HOME|150706|150707|来自flob的一行拷贝，归功于他们|BOLD|150708|entityMap^0|E|4|L|3|R|1|0|0|0|12|I|0|E|4|L|3|R|1|0|0|0|0|2|4|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]|$9|1H|A|1I|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1J|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|1K|8|@]|D|@]|E|$K|L]]|$1|U|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1M|8|@$9|1N|A|1O|B|X]]|D|@]|E|$]]|$1|Y|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]]|Z|$]]

1...Using the short cut <code>Ctlr</code> + <code>Alt</code> + <code>T</code> to open terminal

2...Execute the below command:

<pre><code>echo export JAVA_HOME='$(readlink -f /usr/bin/javac | sed "s:/bin/javac::")' | sudo tee /etc/profile.d/jdk_home.sh &gt; /dev/null
</code></pre>

3...(Recommended) Restart your VM / computer. You can use <code>source /etc/source</code> if don't want to restart computer

4...Using the short cut <code>Ctlr</code> + <code>Alt</code> + <code>T</code> to open terminal

5...Verified JAVA_HOME installment with 

<pre><code>echo $JAVA_HOME
</code></pre>

<hr>

One-liner copy from flob, credit to them

blocks|key|154682|text|张贴作为答案，因为我没有特权来评论。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|154683|指向注意：遵循“那个Dave+Guy”发布的被接受的答案。|offset|length|style|BOLD|154684|设置变量后，请确保对安装该变量的java目录设置了适当的权限。|154685|chmod+-R+755+/usr/java|code-block|syntax|javascript|154686|entityMap^0|0|0|4|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Posting as answer, as I don't have the privilege to comment.

Point to note: follow the accepted answer posted by "That Dave Guy".

After setting the variables, make sure you set the appropriate permissions to the java directory where it's installed.

<pre><code>chmod -R 755 /usr/java
</code></pre>

blocks|key|2948921|text|步骤1-通过"echo+$JAVA_HOME“检查当前java版本|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2948922|第2步-+vim+/etc/profile|2948923|步骤3-在文件的末尾你会发现导出JAVA_HOME，我们需要在这里提供新的路径，确保它不是相对的。|2948924|步骤4-保存并退出:wq|2948925|步骤5-+"source+/etc/profile/"，这将执行更改|2948926|步骤6-再次执行回声$JAVA_HOME+-更改将被反映出来。|2948927|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|P|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|Q|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|S|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|M|$]]

Step 1 - check the current java version by "echo $JAVA_HOME"

Step 2 - vim /etc/profile

Step 3 - At the end of file you will find
export JAVA_HOME, we need to provide the new path here, make sure that it is not relative.

Step 4 - Save and exit :wq

Step 5 - "source /etc/profile/", this would execute the change

Step 6 - Again do a echo $JAVA_HOME - change would have been reflected.

blocks|key|150729|text|所有操作步骤(查找java、父目录、编辑文件等)一种解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|150730|zFileProfile="/etc/profile"
zJavaHomePath=$(readlink+-ze+$(which+java)+%7C+xargs+-0+dirname+%7C+xargs+-0+dirname)
echo+$zJavaHomePath

echo+"export+JAVA_HOME=\"${zJavaHomePath}\""+>>+$zFileProfile
echo+"export+PATH=\$PATH:\$JAVA_HOME/bin"+>>+$zFileProfile|code-block|syntax|javascript|150731|结果：|150732|#+tail+-2+$zFileProfile
export+JAVA_HOME="/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"
export+PATH=$PATH:$JAVA_HOME/bin|150733|解释：|150734|1)让我们将完整的命令分解为几个片段|150735|$(readlink+-ze+$(which+java)+%7C+xargs+-0+dirname+%7C+xargs+-0+dirname)|150736|2)从java命令中查找java路径|150737|#+$(which+java)
"/usr/bin/java"|150738|3)从符号路径中获取相对路径|150739|#+readlink+-ze+/usr/bin/java
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java"|150740|4)获取/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java的父路径|offset|length|style|CODE|150741|#+readlink+-ze+/usr/bin/java+%7C+xargs+-0+dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin"|150742|5)获取/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/的父路径|150743|#+readlink+-ze+/usr/bin/java+%7C+xargs+-0+dirname+%7C+xargs+-0+dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"|150744|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|4|1Q|0|0|4|1M|0|0^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|1E|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|1F|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|1G|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1H|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|1I|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1J|8|@]|9|@]|A|$]]|$1|S|3|T|5|D|7|1K|8|@]|9|@]|A|$E|F]]|$1|U|3|V|5|6|7|1L|8|@]|9|@]|A|$]]|$1|W|3|X|5|D|7|1M|8|@]|9|@]|A|$E|F]]|$1|Y|3|Z|5|6|7|1N|8|@$10|1O|11|1P|12|13]]|9|@]|A|$]]|$1|14|3|15|5|D|7|1Q|8|@]|9|@]|A|$E|F]]|$1|16|3|17|5|6|7|1R|8|@$10|1S|11|1T|12|13]]|9|@]|A|$]]|$1|18|3|19|5|D|7|1U|8|@]|9|@]|A|$E|F]]|$1|1A|3|-4|5|6|7|1V|8|@]|9|@]|A|$]]]|1B|$]]

All operational steps(finding java, parent dir, editing file,...) one solution

<pre><code>zFileProfile="/etc/profile"
zJavaHomePath=$(readlink -ze $(which java) | xargs -0 dirname | xargs -0 dirname)
echo $zJavaHomePath

echo "export JAVA_HOME=\"${zJavaHomePath}\"" &gt;&gt; $zFileProfile
echo "export PATH=\$PATH:\$JAVA_HOME/bin" &gt;&gt; $zFileProfile
</code></pre>

Result:

<pre><code># tail -2 $zFileProfile
export JAVA_HOME="/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"
export PATH=$PATH:$JAVA_HOME/bin
</code></pre>

Explanation:

1) Let's break the full command into pieces

<pre><code>$(readlink -ze $(which java) | xargs -0 dirname | xargs -0 dirname)
</code></pre>

2) Find java path from java command

<pre><code># $(which java)
"/usr/bin/java"
</code></pre>

3) Get relative path from symbolic path

<pre><code># readlink -ze /usr/bin/java
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java"
</code></pre>

4) Get parent path of <code>/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/java</code>

<pre><code># readlink -ze /usr/bin/java | xargs -0 dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin"
</code></pre>

5) Get parent path of <code>/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64/bin/</code>

<pre><code># readlink -ze /usr/bin/java | xargs -0 dirname | xargs -0 dirname
"/usr/lib/jvm/java-11-openjdk-11.0.7.10-1.el8_1.x86_64"
</code></pre>

blocks|key|2948647|text|这可能是一个好主意，无论你编辑的个人资料来源，以避免不得不使用一个新的登录。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2948648|或者:+source+/etc/或者。/etc/|2948649|你编辑过的资料在哪里。|2948650|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

Probably a good idea to source whatever profile you edit to save having to use a fresh login.

either:
source /etc/
or
. /etc/

Where is whatever profile you edited.

blocks|key|2735907|text|在Linux上，我将这一行添加到~/.profile中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2735908|export+JAVA_HOME=$(readlink+-ze+/usr/bin/javac+%7C+xargs+-0+dirname+-z+%7C+xargs+-0+dirname)|code-block|syntax|javascript|2735909|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

On Linux I add this line to my ~/.profile:

<pre><code>export JAVA_HOME=$(readlink -ze /usr/bin/javac | xargs -0 dirname -z | xargs -0 dirname)
</code></pre>

blocks|key|2735964|text|在我们准备设置JAVA_HOME的同时，让我分享一下设置JAVA_HOME或任何其他环境变量的一些好处：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2735965|1)升级JDK很容易，而不会影响应用程序的启动和指向JAVA_HOME的配置文件。您只需下载新版本，并确保您的JAVA_HOME指向新版本的Java。这是使用环境变量或链接的最佳好处。|2735966|2)+JAVA_HOME变量简明简洁，不是JDK安装目录的完整路径。|2735967|3)+JAVA_HOME变量是平台无关性的，即如果您的启动脚本使用JAVA_HOME，则无需任何修改即可在Windows和UNIX上运行，您只需在各自的操作系统上设置JAVA_HOME即可。|2735968|阅读更多：http://javarevisited.blogspot.com/2012/02/how-to-set-javahome-environment-in.html#ixzz4BWmaYIjH|offset|length|2735969|entityMap|0|LINK|mutability|MUTABLE|url|http://javarevisited.blogspot.com/2012/02/how-to-set-javahome-environment-in.html#ixzz4BWmaYIjH^0|0|0|0|0|5|2N|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|V|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|W|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@$J|Y|K|Z|1|10]]|A|$]]|$1|L|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|S]]]]

While we are up to setting JAVA_HOME, let me share some benefits of setting JAVA_HOME or any other environment variable:

1) It's easy to upgrade JDK without affecting your application startup and config file which points to JAVA_HOME. you just need to download new version and make sure your JAVA_HOME points to new version of Java. This is best benefit of using environment variable or links.

2) JAVA_HOME variable is short and concise instead of full path to JDK installation directory.

3) JAVA_HOME variable is platform independence i.e. if your startup script uses JAVA_HOME then it can run on Windows and UNIX without any modification, you just need to set JAVA_HOME on respective operating system.

Read more: <a href="http://javarevisited.blogspot.com/2012/02/how-to-set-javahome-environment-in.html#ixzz4BWmaYIjH" rel="nofollow">http://javarevisited.blogspot.com/2012/02/how-to-set-javahome-environment-in.html#ixzz4BWmaYIjH</a>

blocks|key|2736206|text|在/etc/profile中，如果您打开该文件，您将知道不建议在该文件上写入。请转到/etc/profile.d文件夹并将test.sh放入其中，而不是为命令编写脚本(假设为profile.d)。每次实例重启时，/etc/profile都会自动调用它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2736207|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In /etc/profile , if you open that will you’ll get to know that IT IS no recommended to write on that file. Instead of that make a script of your commands(suppose test.sh)go to /etc/profile.d folder and Put test.sh there. Every time you instance reboot it’ll be automatically called by /etc/profile.

blocks|key|150710|text|使用SDKMAN+sdkman.io切换btw。你的sdk。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|150711|它会为您设置JAVA_HOME。|150712|entityMap|0|LINK|mutability|MUTABLE|url|http://sdkman.io/^0|9|9|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@$A|O|B|P|1|Q]]|C|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|M]]]]

Use SDKMAN <a href="http://sdkman.io" rel="nofollow noreferrer">sdkman.io</a> to switch btw. your sdk's.

It sets the JAVA_HOME for you.

blocks|key|2948981|text|使用sudo打开kafka-run-class.sh以写入|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2948982|您可以在kafka文件夹中找到kafka-run-class.sh：kafka/bin/kafka-run-class.sh|2948983|检查是否有这些行|2948984|​|2948985|📷|atomic|2948986|2948987|修改else部分中的JAVA变量，使其指向java/bin中的java可执行文件。像JAVA="$JAVA_HOME/java"一样|2948988|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/e3c4e8d90487b368c2a04064882459cb.png|imageAlt^0|8|I|0|F|I|Y|S|0|0|0|0|1|0|0|0|16|M|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|18|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|19|8|@]|D|@]|E|$]]|$1|L|3|M|5|N|7|1A|8|@]|D|@$9|1B|A|1C|1|1D]]|E|$]]|$1|O|3|K|5|6|7|1E|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1F|8|@$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|R|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|S|$T|$5|U|V|W|E|$X|Y|Z|-4]]]]

open kafka-run-class.sh with sudo to write

you can find kafka-run-class.sh in your kafka folder : kafka/bin/kafka-run-class.sh

check for these lines

<a href="https://i.stack.imgur.com/Gn6ox.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Gn6ox.png" alt="enter image description here"></a>

Modify the JAVA variable in the else part to point to the java executable in your java/bin. like JAVA="$JAVA_HOME/java"

blocks|key|150762|text|对于新用户来说，使用vim可能有点困难。我们可以使用gedit文本编辑器来代替。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|150763|Find+/usr/lib/jvm/java-1.x.x-openjdk的|150764|ordered-list-item|150765|150766|如果以not-privileged身份登录，配置文件可输入"gedit+/etc/|150767|“或使用"sudo+gedit+/etc/profile”|150768|150769|150770|在行尾添加以下内容：|150771|150772|导出JAVA_HOME=“找到的路径”|150773|导出PATH=$JAVA_HOME/bin:$PATH|150774|150775|在当前|150776|中输入"source+/etc/profile“以应用更改|150777|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|-4|5|E|7|12|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|E|7|15|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|M|3|N|5|E|7|18|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1A|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|1B|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|U|3|V|5|E|7|1D|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|Z|$]]

Using vim might be a bit difficult for new user. We can use gedit text editor instead.
<ol>
<li>Find /usr/lib/jvm/java-1.x.x-openjdk
</li>
<li>Enter &quot;gedit /etc/profile&quot; or use &quot;sudo gedit /etc/profile&quot; if logged in as not-privileged
</li>
<li>Add the following at the end of line:
export JAVA_HOME=&quot;path that you found&quot;
export PATH=$JAVA_HOME/bin:$PATH
</li>
<li>Enter &quot;source /etc/profile&quot; in your current shell to apply the changes
</li>
</ol>

blocks|key|153208|text|我用下面这句话：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|153209|export+JAVA_HOME=$(readlink+-f+$(dirname+$(readlink+-f+$(which+java)+))/../)|code-block|syntax|javascript|153210|添加到我的~/.profile，以便它在登录时使用缺省java目录的基目录。这是为了狂欢。|153211|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I use the line:

<pre><code>export JAVA_HOME=$(readlink -f $(dirname $(readlink -f $(which java) ))/../)
</code></pre>

to my ~/.profile so it uses the base of the default java directory at login time. This is for bash.

I am new to Linux system and there seem to be too many Java folders. 

java -version gives me:

<ul>
<li>java version "1.7.0_55"</li>
<li>OpenJDK Runtime Environment (rhel-2.4.7.1.el6_5-x86_64 u55-b13)</li>
<li>OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)</li>
</ul>

When I am trying to build a Maven project , I am getting error:

<pre><code>Error: JAVA_HOME is not defined correctly.
We cannot execute /usr/java/jdk1.7.0_05/bin/java
</code></pre>

Could you please tell me which files I need to modify for root as well as not-root user and where exactly is java located?

How to set JAVA_HOME in Linux for all users

服务器

Windows

Linux

Java

我是Linux系统的新手，似乎有太多的Java文件夹。java -version为我提供了：服务器java版本"1.7.0_55"OpenJDK运行时环境(rhel 2.4.7.1.el6_5-x86_64 u55-b13)OpenJDK 64位 VM (内部版本24.51-b03，混合模式))当我试图构建一个Maven项目时，我得到了错误：Error: JAVA_HOME is not defi

问如何在Linux中为所有用户设置JAVA_HOME
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