after enctype="multipart/form-data" request not working

Question

public class Relay extends HttpServlet {   
    @Override
    public void service(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String command = request.getParameter("command");
        RequestDispatcher rd =request.getRequestDispatcher(command);
        rd.forward(request, response);
        System.out.println("Request forwarded to " + command + " servlet");
    }
}

This is my Relay servlet, I'm sending data from this form

<form action="Relay" method="POST" enctype="multipart/form-data"> /
    <input type="hidden" name="command" value="AddProduct" />
    <input type="text" name="pname" value="" />
    <input name="" type="submit" value="Add Product">
</form>

It is throwing a java.lang.NullPointerException.

But works fine when I remove this:

enctype="multipart/form-data"

Answer 1

Why do you need to add it then? Just keep it out.

If you need it in order to upload a file by <input type="file"> which you intend to add later on, then you should put @MultipartConfig annotation on your servlet, so that request.getParameter() will work and that all uploaded files can be retrieved by request.getPart().

@WebServlet("/Relay")
@MultipartConfig
public class Relay extends HttpServlet {   
    // ...
}

See also:

• How to upload files to server using JSP/Servlet?

Answer 2

Parameters encoded with multipart/form-data are sent in POST body - not as regular request parameters, therefore can't be read using request.getParamter(...).

Check out Commons file upload package for multipart requests processing.