spring:bind error when converting empty input field to Long

I am using a SimpleFormController with Spring:bind tag on my jsp and a validator object.

I have a simple Long property which maps to a simple input field, it validates numbers ok but if no value is entered at all it throws a conversion error.

Please how do I handle this simple case, surely I dont have to write a property editor for this.

Where is it throwing? In the validator or in the view?

Can you show us the code where it's throwing?

By default, the CustomNumberEditor doesn't accept empty/null input. Put the following line in your controller initbinder() method:

Code:

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binder.registerCustomEditor(Long.class, new CustomNumberEditor(Long.class, true));

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I tried that and was pretty confident it would solve the prpblem but it hasnt actually made any difference, the exact error I get is:
Failed to convert property value of type [java.lang.String] to required type [java.lang.Long] for property 'volume'; nested exception is java.lang.NumberFormatException: For input string: " "

Sorry I had only done a deploy not a real build, it has made a difference but code now falls over when I call ValidationUtils in my validator to validate the field, I will try subclassing the CustomNumberEditor

ok, problem solved by creating the following class and registering it with initBinder

Code:

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import org.springframework.beans.propertyeditors.CustomNumberEditor;
import org.springframework.util.NumberUtils;
import org.springframework.util.StringUtils;

public class LongAllowsBlanksEditor extends CustomNumberEditor
{
    public LongAllowsBlanksEditor()
    {
        super(Long.class, true);
    }

    /**
    * Parse the Number from the given text, using the specified NumberFormat.
    */
    public void setAsText(String text) throws IllegalArgumentException
    {
        super.setAsText(text);
        if(getValue()==null)
        {
            setValue(new Long(0));           
        }     
    }
}

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