System.getenv() gets environment variables.
System.getProperty() obtains the parameters set by the java startup script, such as java -jar -Dsrping.profiles.active=dev.
At this time, using System.getProperty("srping.profiles.active") returns dev.
When writing, it is recommended to have a priority concept, such as using System.getProperty() to get it first, if not, then get it from System.getenv(), if not, then perform corresponding business processing