系统环境变量：
| Key | Meaning |
|---|---|
"file.separator" |
Character that separates components of a file path. This is "/" on UNIX and "\" on Windows. |
"java.class.path" |
Path used to find directories and JAR archives containing class files. Elements of the class path are separated by a platform-specific character specified in the path.separator property. |
"java.home" |
Installation directory for Java Runtime Environment (JRE) |
"java.vendor" |
JRE vendor name |
"java.vendor.url" |
JRE vendor URL |
"java.version" |
JRE version number |
"line.separator" |
Sequence used by operating system to separate lines in text files |
"os.arch" |
Operating system architecture |
"os.name" |
Operating system name |
"os.version" |
Operating system version |
"path.separator" |
Path separator character used in java.class.path |
"user.dir" |
User working directory |
"user.home" |
User home directory |
"user.name" |
User account name |
代码举例：
// 获取当前的工作目录 String userDir = System.getProperty("user.dir"); log.info("userDir:[{}]" + userDir); // 信息: userDir:[{}]E:\workspace\XXX // 获取所有系统变量 Properties properties = System.getProperties(); log.info("properties:【{}】" + properties.toString());
参考文档：
https://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html
原文：https://www.cnblogs.com/gongxr/p/14262435.html