public static CheckinGroup load(String file){
		CheckinGroup data = new CheckinGroup();
		try {
			File f =new File(file);
			FileInputStream fis= new FileInputStream(f);
			int len = fis.available();
			byte[] data1 = new byte[len];
			fis.read(data1);
			fis.close();
			String dataStr = new String(data1,"UTF-8");
			
			String[] lines = dataStr.split("\n");
			
			Date date ;
			
			DateFormat fmt =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
			
			for(int i = 0 ; i<lines.length;i++){
				if(!lines[i].equals("")){
					
					String[] part = lines[i].split(";");
					Checkin item = new Checkin();
					String key = "";
					if(part.length > 0 && part[0]!=null && !part[0].equals("")){
						
						date = fmt.parse(part[0]);
						key = new SimpleDateFormat("yyyyMMdd").format(date);
						item.date = key ;
						item.checkin = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date);
					}else{
						continue ;
					}
					
					if(part.length > 1 && part[1]!=null && !part[1].equals("")){
						date = fmt.parse(part[1]);
						item.checkout = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date);
					}else{
						item.checkout = "";
					}
					data.put(key, item);
				}
			}
			data.setStorePath(file);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return data;
	}