환경변수 값 읽어오기.

OS / JVM 환경변구 값 읽어오기.

public static void main( String[] args ) {
                System.out.println("OS 환경변수 값");
                System.getenv().entrySet().forEach(e -> {
                        System.out.println("\t" + e.getKey() + "=" + e.getValue());
                });
                // export java_test_value="TEST VAL"
                System.out.println("OS 환경변수 java_test_value 값 = " + System.getenv("java_test_value"));


                System.out.println("");
                System.out.println("JVM 환경변수 값");
                Properties props = System.getProperties();
                for(Enumeration en = props.propertyNames(); en.hasMoreElements();) {
                        String key = (String)en.nextElement();
                        String value = props.getProperty(key);
                        System.out.println("\t" + key + "=" + value);
                }
                System.out.println("JVM 환경변수 user.name값 = " + System.getProperty("user.name"));
                System.out.println("JVM 환경변수 user.test값 = " + System.getProperty("user.test", "user.test property is null."));
}