#java: create folder by dateTime, write text file multi time

Calendar now = Calendar.getInstance();
        String dateTime = now.get(Calendar.DAY_OF_MONTH) + "-" + now.get(Calendar.MONTH) +"-"+ now.get(Calendar.YEAR);
        File folder = new File("logs/"+ dateTime);
        if(!folder.exists())
            folder.mkdirs();

        File file = new File(folder+"/log_"+now.get(Calendar.HOUR_OF_DAY)+"h.txt");
        if(!file.exists())
            file.createNewFile();


        BufferedWriter writer = new BufferedWriter(new FileWriter(file.getAbsoluteFile(), true));
        writer.write(now.get(Calendar.HOUR_OF_DAY)+": Sttd "+"\n");
        writer.close();