Linux下java环境变量配置，解决重新打开bash后JDK环境变量无效

Linux下配置JDK实际上是很简单的，我按照网上的教程进行如下配置，在 /etc/profile 文件中最后添加：

export JAVA_HOME=/home/son/jdk1.8.0_144

export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

export PATH=$JAVA_HOME/bin:$PATH

 

通过命令启用java环境：

source /etc/profile

 

但是有一个问题比较恶心，那就是JDK环境变量失效的问题，关闭设置好的bash后重新打开，java环境变量就无效了

root@ubuntu:/home/son/apache-tomcat-8.5.20/bin# ./shutdown.sh 

Neither the JAVA_HOME nor the JRE_HOME environment variable is defined

At least one of these environment variable is needed to run this program

root@ubuntu:/home/son/apache-tomcat-8.5.20/bin# java -version

bash: java: command not found

 

经大神指点， /etc/profile 文件修改一下，删除 export 就行。

JAVA_HOME=/home/son/jdk1.8.0_144

CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

PATH=$JAVA_HOME/bin:$PATH

 

需要再启用一下

source /etc/profile

 

再运行一下java

root@ubuntu:/etc# java

Usage: java [-options] class [args...]

(to execute a class)

or  java [-options] -jar jarfile [args...]

(to execute a jar file)

where options include:

-d32  use a 32-bit data model if available

-d64  use a 64-bit data model if available

-server  to select the"server" VM

The default VM is server, because you are running on a server-class machine.

-cp

-classpath

A : separated list of directories, JAR archives, and ZIP archives to search for class files.

-D=

set a system property

-verbose:[class|gc|jni]

enable verbose output

-version      print product version and exit

-version:

Warning: this feature is deprecated and will be removed in a future release. require the specified version to run

-showversion  print product version and continue

-jre-restrict-search | -no-jre-restrict-search

Warning: this feature is deprecated and will be removed in a future release. include/exclude user private JREs in the version search

-? -help      print this help message

-X            print help on non-standard options

-ea[:...|:]

-enableassertions[:...|:]

enable assertions with specified granularity

-da[:...|:]

-disableassertions[:...|:]

disable assertions with specified granularity

-esa | -enablesystemassertions

enable system assertions

-dsa | -disablesystemassertions

disable system assertions

-agentlib:[=]

load native agent library , e.g. -agentlib:hprof see also, -agentlib:jdwp=help and -agentlib:hprof=help

-agentpath:[=]

load native agent library by full pathname

-javaagent:[=]

load Java programming language agent, see java.lang.instrument

-splash:

show splash screen with specified image

See http://www.oracle.com/technetwork/java/javase/documentation/index.html for more details.

 

OK!