The solution is to re-source /etc/profile every time you enter the command to take effect

#编辑JDK8
export JAVA_HOME="/usr/java/java8"

#编辑maven
export M2_HOME="/opt/idea-IU-162.1121.32/plugins/maven/lib/maven3"

#编辑PATH
export PATH="$JAVA_HOME/bin:$M2_HOME/bin:$PATH"

This is the configuration at the end of my /etc/profile. There is no problem with JDK, no source is needed, and echo $JAVA_HOME can come out. The problem is that if you want to use mvn, you need to source it every time. I use IDEA for maven. with.

solution:

The configuration can be placed in ~/.bashrc. Or add a source /etc/profile to ~/.bashrc