Posted on Aug 29, 2020
Sometimes you want to change the behavior of your code without recompiling or deploying. One way to do this is by defining environment variables that you can change at any time. A typical use case is for database connection properties (username, password, port, etc).
In your Tomcat home create this file
$TOMCAT_HOME/bin/setenv.sh and define variables like this:
Grant execution permission
export VAR1=my_var1_value export VAR2=my_var2_value
In Windows define variables like this:
chmod 755 setenv.sh
After saving the file you must reboot Tomcat.
In your code you get the environment variable this way:
//value will be null if VAR1 does not exist String value = System.getenv("VAR1");