oracle.comSystem Properties (The Java™ Tutorials > Essential Java Learn how to read and write system properties using the System class and Properties objects. System properties are configuration settings for the Java platform environment.更多内容请查看https://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html
Oracle Help CenterThe System.setProperty(String, String) method sets the system property indicated by the specified key to the specified value. It returns the previous value of the property or null if the 更多内容请查看https://docs.oracle.com/javase/8/docs/api/java/lang/System.html