How to use an Alert without giving Refresh on the Page?

Question

So, I’m doing a client registration with Java web (jsp) and Servlet, where I receive in my registration database the form data and check if there is already Cpf. The code goes right down.

try {

                String nome = request.getParameter("nome");
                String cpf = request.getParameter("cpf");
                String telefone = request.getParameter("telefone");
                String email = request.getParameter("email");
                String senha = request.getParameter("senha");
                String cep = request.getParameter("cep");
                String cidade = request.getParameter("cidade");
                String uf = request.getParameter("uf");
                String bairro = request.getParameter("bairro");
                String endereco = request.getParameter("endereco");
                String complemento = request.getParameter("complemento");
                int numero = Integer.parseInt(request.getParameter("numero"));

                Cliente c = new Cliente();
                c.setNome(nome);
                c.setCpf(cpf);
                c.setTelefone(telefone);
                c.setEmail(email);
                c.setSenha(senha);
                c.setCep(cep);
                c.setCidade(cidade);
                c.setUf(uf);
                c.setBairro(bairro);
                c.setEndereco(endereco);
                c.setComplemento(complemento);
                c.setNumero(numero);

                ClienteDAO cDAO = new ClienteDAO();
                Cliente c2 = new Cliente();
                c2 = cDAO.carregaPorCpf(cpf);

                if (!c.getCpf().equals(c2.getCpf())) {
                    cDAO.inserir(c);
                    
                    response.sendRedirect("index.jsp");
                } else {
                    out.println("<script type='text/javascript'>");
                    out.println("alert('CPF já cadastrado !')");
                    out.println("window.open('form_autocadastrar_cliente.jsp','_self')";);
                    out.println("</script>");
                }

} catch (Exception e) {
   out.print("Erro: " + e);
}

It’s working perfectly but my only problem and this out.println("window.open('form_autocadastrar_cliente.jsp','_self')";); which after clicking OK, in the Alert message, refresh it on the page and reset all the form data.

It is possible to do the directing without giving refresh?

Answer 1

Searching here I got a way not to reset the form instead of window.open('formulario') used the history.back('formulario').

out.println("history.back('form_autocadastrar_cliente.jsp','_self');");