@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		Map<String,String> fouten = new HashMap<>();
		BigDecimal percentage = null;
		try {
			percentage = new BigDecimal(request.getParameter("percentage"));
			if (percentage.compareTo(BigDecimal.ZERO) <= 0) {
				fouten.put("percentage", "tik een positief getal");
			}
		} catch (NumberFormatException ex) {
			fouten.put("percentage", "tik een positief getal");
		}
		if (fouten.isEmpty()) {
			artikelService.prijsverhoging(percentage);
			response.sendRedirect(request.getContextPath());
		} else {
			request.setAttribute("fouten", fouten);
			request.getRequestDispatcher(VIEW).forward(request, response);
		}
	}