public void addCategory(HttpServletRequest request, HttpServletResponse response) {
		String categoryName = request.getParameter("categoryName");
			
		BookCategoryDAO bcdao = new BookCategoryDAO();		 
		BookCategory bc = bcdao.querryUseName(categoryName);
		
		
		if(bc.getName()==null) {
			bc=new BookCategory();
			bc.setName(categoryName);
			bcdao.insert(bc);
		}
		try {
			response.sendRedirect("../managerView/categoryManage.jsp");
		} catch(Exception e) {
			e.printStackTrace();
		}		
	}