How to bind Spring form:checkbox instead of form:checkboxes? - spring

Question

I am having problems with form:checkbox. I cannot make it display selected values. When I selected values and submit, correct values are display in database. When I load page all values (checkboxes) are not selected.
Elements below are located inside this:
<form:form role="form" commandName="user" class="form-horizontal" action="${form_url}">
</form:form>
This works just fine:
<form:checkboxes items="${availableRoles}" path="roles" itemLabel="role" itemValue="id" element="div class='checkbox'"/>
This doesn't work:
<c:forEach items="${availableRoles}" var="r" varStatus="status">
<div class="checkbox">
<form:checkbox path="roles" label="${r.description}" value="${r.id}"/>
</div>
</c:forEach>
This is my domain class:
public class User {
private List<Role> roles;
public List<Role> getRoles() {
return roles;
}
public void setRoles(List<Role> roles) {
this.roles = roles;
}
This is my custom property editor:
public class RolePropertyEditor extends PropertyEditorSupport {
#Override
public void setAsText(String text) {
Role role = new Role();
role.setId(Integer.valueOf(text));
setValue(role);
}
}
Controller has this method:
#InitBinder
public void initBinder(WebDataBinder binder) {
binder.registerCustomEditor(Role.class, new RolePropertyEditor());
}
Controller method:
#RequestMapping(value = "/update/{userId}", method = RequestMethod.GET)
public String updateUser(#PathVariable Integer userId, Model model) {
User user = userService.getByUserId(userId);
List<Role> availableRoles = roleService.getAllRoles();
model.addAttribute("availableRoles", availableRoles);
model.addAttribute("user", user);
return "user/update";
}

Answer 1

After debugging session I found the solution.
Because of Spring internals JSP should look like this:
<c:forEach items="${availableRoles}" var="r">
<div class="checkbox">
<form:checkbox path="roles" label="${r.description}" value="${r}" />
</div>
</c:forEach>
Notice that value is item (r), not item's member like r.id.
Also you need getAsText implementation in your custom PropertyEditor.
#Override
public String getAsText() {
Role role = (Role) this.getValue();
return role.getId().toString();
}