public void delete(){
		
		File oldFile = new File(ConstansBook.OLD_DAT_URL);
		
		 if (oldFile.exists()){
		      if (oldFile.delete()){
		        System.out.println("t@C폜܂");
		      }else{
		        System.out.println("t@C̍폜Ɏs܂");
		      }
		    }else{
		      System.out.println("oldt@C܂");
		    }
	}