protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		String operation = request.getParameter("operation");
		
		Command com = null;
		
		if(operation == null){
			com = new ShowCommand();
		} else if(operation.equals("add")){
			com = new AddCommand();
		} else if (operation.equals("addwrite")) {
			com = new AddWriteCommand();
		} else if(operation.equals("edit")){
			com = new UpdateCommand();
		} else if(operation.equals("addupdate")){
			com = new AddUpdateCommand();
		} else if(operation.equals("delete")){
			com = new DeleteCommand();
		} else if(operation.equals("adddelete")){
			com = new AddDeleteCommand();
		}

		com.execute(request, response);
	}