java getEnv不区分大小写 getProperty区分大小写

System.out.println(System.getenv("JAVA_HOME"));  

System.out.println(System.getenv("Path"));  

System.out.println(System.getenv("PATH"));//不区分大小写

System.out.println(System.getenv("Tmp"));  



System.out.println("-------------------------------------");  

System.out.println(System.getProperty("os.name"));  

System.out.println(System.getProperty("OS.NAME"));//区分大小写

System.out.println(System.getProperty("temp"));  

System.out.println(System.getProperties());