/**
 * Servlet implementation class SasieBranche
 */
@WebServlet("/SasieBranche")
public class SasieBranche extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public SasieBranche() {
        super();
      
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String lib = request.getParameter("LIB");
		int id = Integer.parseInt(request.getParameter("ID"));
		try {
			Branche.SaisieBranche(id,lib);
		} catch (ClassNotFoundException | SQLException e) {
			
			e.printStackTrace();
		}
		
		getServletContext().getRequestDispatcher("/Confirmation.jsp").forward(request, response);

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		
		}
		
	
	
	
	      
	
	

}

Tu l'attaque bien en get ? et passe tu bien dans la méthode ?