BindException while trying to bind empty form field to float (primitiv)

[tunguska]

Hi,

As it's in the title, I get a BindException, trying to validate a form field:

Model:

public abstract class AbstractMaterial {
   
   // auto generated
   private float volume;
}

View:

<c:forEach items="${helper.materials}" var="material" varStatus="loop">

     <td><form:input path="materials[${loop.index}].volume"/></td>

</c:forEach>

Controller:

@InitBinder
protected void initBinder(HttpServletRequest request, ServletRequestDataBinder binder){	
   binder.registerCustomEditor(Date.class, new CustomDateEditor(SystemGlobals.europeDateFormat, true));		
   binder.registerCustomEditor(String.class, new StringTrimmerEditor(true));		
}

Exception:

Field error in object 'helper' on field 'materials[0].volume': rejected value []; codes [typeMismatch.helper.materials[0].volume,typeMismatch.helper.materials.volume,typeMismatch.materials[0].volume,typeMismatch.materials.volume,typeMismatch.volume,typeMismatch.float,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [helper.materials[0].volume,materials[0].volume]; arguments []; default message [materials[0].volume]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'float' for property 'materials[0].volume'; nested exception is java.lang.NumberFormatException: empty String]

I use spring only since a short time and therefore I am very grateful for any help.

[Marten Deinum]

And your problem is? YOu are using a primitive a primitive cannot be null so an empty string cannot be converted...