Understanding the concept of data binding in a Spring-MVC application

Question

I am trying to understand the concept of data binding in Spring-MVC with Velocity (I study this structure and port the application to this platform).

I use to get form variables, using request.getParameter("username"), in the Spring world, it seems that I can perform validation against form objects as well. A datamodel style object that represents all form fields.

The validator concept makes sense, but the data marshalling from the query string for these objects is still vague for me. Is this the right concept for data binding?

If I relate to this issue a few specific questions:

• When a "binding" is created between a form variable (for example "username"), and an object field (for example org.a.b.MyNewUserFormObj.username) is a "binding" of a constant definition, so that all subsequent HTTP messages do this form cause the form variable usernameto be assigned org.a.b.MyNewUserFormObj.username?
• How in the world can I fulfill the above definition of binding? (if what I said so far is true, I feel like Costello in "Who Is First", I don’t even know what I just said!), I just need a conceptual picture.

Thank you for establishing that the brain is crazy.

Answer 1

There is no data binding in the data binding.

, Spring @ModelAttribute ( , , ).

,

<input type = "text" name = "firstName" />

public class Person {
    private String firstName;
    ... getters, setters ...
}

.

Spring HTML-. , JSP:

<form:form modelAttribute = "person" ...>
    <form:input path = "firstName" />
</form:form>

Velocity ( , <form> , ):

<form ...>
    #springFormInput("person.firstName" "")
</form>

, , model ( ).