I'm developing a web page using Java Servlets and JSP. I have functionality where, depending on the received action (action), different operations are performed. However, I'm encountering an issue with a specific action (action4) which should generate a PDF and then redirect the user to another page.
Questions:
- How can I correctly redirect to a page after generating the PDF?
- Is there a way to complete the PDF download and then perform the redirection?
I appreciate any help or suggestions you can offer. Thanks in advance!
Below is my structure and the problem I'm facing.
Servlet:
if (action != null) {
switch (action) {
case "action1": // Add items to cart
if (carritoSQL.existeProducto(producto)) {
handleAddButton(request, response, producto, cantidad, carrito);
}
break;
case "action2": // Development-focused case
handleClearButton(request, response, session);
break;
case "action3": // Cancel purchase
handleClearButton(request, response, session);
redirect = "views/home.jsp";
break;
case "action4": // Complete purchase
handleCompletePurchaseButton(request, response, fecha, vendedor, distribuidor, carrito);
handleClearButton(request, response, session);
request.getRequestDispatcher("views/home.jsp").forward(request, response);
//redirect = "views/home.jsp";
break;
default:
// Default logic if necessary
defaultHandler(request, response);
redirect = "views/home.jsp";
break;
}
} else {
// Handle the case where no 'action' value is received
defaultHandler(request, response);
}
response.sendRedirect(redirect);
private void handleCompletePurchaseButton(HttpServletRequest request, HttpServletResponse response, String fecha, String vendedor, String distribuidor, ShoppingCart carrito) throws ServletException, IOException {
GeneralReceipt receipt = createReceipt(fecha, vendedor, distribuidor, carrito);
detailReceipt(receipt.getId(), fecha, vendedor, distribuidor, carrito);
String ticket = generateTicketString(vendedor, distribuidor, carrito, receipt);
generatePDF(response, ticket, distribuidor, fecha);
}
Problem: The issue occurs with action4. The operation correctly generates the PDF, which is then downloaded by the user, but the redirection to the page does not occur. I tried the following solutions:
- response.sendRedirect("views/home.jsp");
- request.getRequestDispatcher("views/home.jsp").forward(request, response);
Both solutions result in the following error in the console:
28-Jun-2024 10:50:29.355 SEVERE [68] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [operacionesRemisionNH1] threw exception
java.lang.IllegalStateException: Cannot call sendRedirect() after the response has been committed
at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:486)
at Servlets.operacionesRemisionNH1.generatePDF(operacionesRemisionNH1.java:354)
at Servlets.operacionesRemisionNH1.handleCompletePurchaseButton(operacionesRemisionNH1.java:153)
at Servlets.operacionesRemisionNH1.doPost(operacionesRemisionNH1.java:114)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:232)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:167)
JSP where I call action4:
<div class="modal fade" id="FinalizarCompraModal" tabindex="-1" aria-labelledby="FinalizarCompraModalLabel" aria-hidden="true">
<div class="modal-dialog modal-dialog-centered">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="FinalizarCompraModalLabel">Purchase Confirmation</h5>
<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button>
</div>
<div class="modal-body">
You are about to complete your purchase. Please review your order details. If everything is correct, click 'Confirm' to complete the purchase. If you need to make any changes, click 'Cancel'.
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Cancel</button>
<button type="submit" name="action" value="action4" class="btn btn-primary">Confirm</button>
</div>
</div>
</div>
</div>