Java识别操作系统

 /**
  * Created by xfyou on 2016/11/3.
  */
 public class SysDep {
     final static String UNIX_NULL_DEV = "/dev/null";
     final static String WINDOWS_NULL_DEV = "NULL";
     final static String FAKE_NULL_DEV = "jnk";

     public static String getDevNull() {
         if (new File(UNIX_NULL_DEV).exists()) {
             return UNIX_NULL_DEV;
         }
         String sys = System.getProperty("os.name");
         if (sys == null) {
             return FAKE_NULL_DEV;
         }
         if (sys.startsWith("Windows")) {
             return WINDOWS_NULL_DEV;
         }
         return FAKE_NULL_DEV;
     }

     public static void main(String[] args) {
         System.out.println(getDevNull());
     }
 }