JavaBean JSP to Servlet

Question

Presuming this is an easy one.
I have created a JavaBean in a JSP page that submits a form to a Servlet, how do I send the JavaBean to the Servlet?
I know how to create a JavaBean in a Servlet and send it to a JSP page but not vise versa.

Answer 1

The bean you created in the JSP no longer exists when the returning form content hits the servlet, it's a new transaction.
So the first thing the servlet needs to do is to create a new instance of the bean and load data from the parameters into the corresponding bean attributes. There are library classes in Spring, Struts or apache commons to do this stuff, or you can simply do it yourself like:
MyDto dto = new Dto();
dto.setField1(request.getParameter("field1"));
..  etc.It's likely that the servlet will store this bean as a request attribute before forwarding to the JSP. It's also likely that you'll have to validate some of the fields, especially if the bean has non - String attributes.
(This is a major area where frameworks like struts or Spring do a lot of this boiler plate stuff for you).