Newbie Spring MVC problem: Collections doesn't binding from form to model

[dcasanueva]

Hi!
I'm newbie in Spring MVC, and i have a problem that making me crazy!
I have a form with a <select> multiple (the values of a Collection), but when i view the database, there are all the fields of the class, but not the Collection. My code is this:

Bean: Libro, parent of the relationship

public class Libro {

	
    private Long isbn;
    private String titulo = "";
      .......  
   private Set<Autor> autores = null;  }

Bean: Autor, childs

public class Autor {

    private String apellidoPaterno = "";
    private String apellidoMaterno = "";
    private String nombres = ""; 
    private Long id; }

Controller: AdminLibroRegisterFormController

public class AdminLibroRegisterFormController extends
		AbstractWizardFormController {
.....
	

    protected void initBinder(HttpServletRequest request,
			ServletRequestDataBinder binder) {

    binder.registerCustomEditor(Autor.class, new AutorSupport());

	}

.....

}

Support for Autor: AutorSupport

public class AutorSupport extends PropertyEditorSupport {

	private ICatalogoService catalogoService;
.....

    public void setAsText(String string)
          throws IllegalArgumentException {
 
    	try {
       
        	Long id = Long.valueOf(string);
        	Autor a = catalogoService.findAutorById(id);
        	
        	if(a==null){
        		throw new IllegalArgumentException("Id de Autor Inválido");
        	}
        	
        	setValue(a);

        } catch (NumberFormatException ex) {
          throw new IllegalArgumentException("Invalid id for Autor: " + string);
        } 
      }

.....    
    }

JSP Page

	

....
<tr>
		<th><label for="autor" class="required"> * <fmt:message
			key="libro.autor" />:</label></th>
		<td><spring:bind path="libro.autores">
			<select name="autor" multiple>
				<c:forEach var="autor" items="${autores}">
					<option value="<c:out value="${autor.id}"/>"><c:out
						value="${autor.nombres}  ${autor.apellidoPaterno}  ${autor.apellidoMaterno}" /></option>
				</c:forEach>
			</select>
		</spring:bind></td>
	</tr>
....

Help me please!!!!!

[dcasanueva]

anyone have a idea? i need to fix this problem

[dcasanueva]

somebody help me please, i work for 5 days in this problem and i test whith all the implementations i've found in the forum, but nothing fix my problem :S

[jlee]

I *think* your problem lies here in your controller custom editor registration:

binder.registerCustomEditor(Autor.class, new AutorSupport());

When it should be:

binder.registerCustomEditor(Set.class, new AutorSupport());

Since your property is not Autor but a Collection of Autor objects, Spring will only set a field of your command object as type Set and not find a match.

Try that.

[Colin Yates]

You might find http://forum.springframework.org/sho...ght=checkboxes useful.

[dcasanueva]

I *think* your problem lies here in your controller custom editor registration:

binder.registerCustomEditor(Autor.class, new AutorSupport());

When it should be:

binder.registerCustomEditor(Set.class, new AutorSupport());

Since your property is not Autor but a Collection of Autor objects, Spring will only set a field of your command object as type Set and not find a match.

Try that.

I change that, but the SetValue method gets a empty HashSet :s

[dcasanueva]

You might find http://forum.springframework.org/sho...ght=checkboxes useful.

i've cheked that topic, but i couldn't find the taglib where is contains(status.value, role)

Thanks for your replies

Pd: sorry if my english isn't not the best... saludos desde Chile

[jlee]

I change that, but the SetValue method gets a empty HashSet :s

Well, that's because setValue gets a String[]. You'll have to then take each String, lookup you object (usually the String is a id of some sort) and then add that to a new Set. The fact that you're getting an entry into the setValue method means that your custom binder registration is working, so you're almost there!

What i did was to keep a local instance of a HashSet in my class. I then got the String[] via the setValue method, which I then did my id lookups, added those objects to the HashSet, and then in the getValue method, I return that HashSet. If you see this post http://forum.springframework.org/showthread.php?t=19603 and scroll down towards the bottom, you'll see what I'm doing with Set.

[Colin Yates]

I am not sure what spring does with Sets, but if you use an array then you do *not* need to register a property editor against the Array.class, merely against your domain class (i.e. Author).

As mentioned in the linked article, this works with Author[], but I am not sure about Set<Author>.

[dcasanueva]

Well, that's because setValue gets a String[]. You'll have to then take each String, lookup you object (usually the String is a id of some sort) and then add that to a new Set. The fact that you're getting an entry into the setValue method means that your custom binder registration is working, so you're almost there!

What i did was to keep a local instance of a HashSet in my class. I then got the String[] via the setValue method, which I then did my id lookups, added those objects to the HashSet, and then in the getValue method, I return that HashSet. If you see this post http://forum.springframework.org/showthread.php?t=19603 and scroll down towards the bottom, you'll see what I'm doing with Set.

Thanks! I understand the problem now ! I will fix it now jejeje