How to open a JSP inside a JSP through a Servlet?

I’m using a Script, but I’m not using Servlet to do the desired action inside my index.jsp page, and do not use this Script below to open a JSP file inside my index.jsp home page.

  <script src="//ajax.googleapis.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>

    <script>
        $(document).ready(function() {
            var domContent = $("#content");

            $(".nav-link").click(function() {
                domContent.load($(this).attr("href"));
                return false;
            });
        });
    </script>

<li class="topmenu"><a class="nav-link" href="cad_conta.jsp" title="Cadastrar uma conta" style="height:19px;line-height:19px;">Cadastro</a></li>

The correct one in a web application is always to create a class servlet every jsp created, to deal with your requests and answers.

In your case you already have a servlet , you should create a new servlet corresponding to the jsp you want to call, examples: jspCadastro , ServletCadastro .

As for the method, you can create a doGet method that will be responsible for calling your jsp using RequestDispacher .
Example:

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.getRequestDispatcher("/WEB-INF/paginas/jspCadastro.jsp").forward(req, resp);
}

In your main%% of%, you only add a button by passing the path of your jsp responsible for that servlet . Example:

<button onclick="window.location=' ServletCadastro '">Cadastrar</button>

calling its jsp by method servlet through doGet .