Thymeleaf - Exception evaluating SpringEL expression on object variable

Question

I am sticking a value into a hidden input with Thymeleaf and keep getting an error that says Caused by: org.attoparser.ParseException: Exception evaluating SpringEL expression: "receiptInquirySearchForm.cardNumber?:''" (template: "results.html" - line 14, col 44)
I have tried putting the ? after receiptInquirySearchForm, after cardNumber, and after both. I keep getting that same error on that line.

Here is line 14:

<input type="hidden" name="cardNumber" data-th-value="${receiptInquirySearchForm.cardNumber?}" />

Now I know receiptInquirySearchForm is a valid non-null object because I have several other hidden inputs that do not throw errors.

<input type="hidden" name="tokenId" data-th-value="${receiptInquirySearchForm.tokenId}" />
<input type="hidden" name="accountNumber" data-th-value="${receiptInquirySearchForm.accountNumber}" />
<input type="hidden" name="sku" data-th-value="${receiptInquirySearchForm.sku}" />

When I change the data-th-value from cardNumber to tokenId, it gets past that block of hidden inputs so every other line works fine.

UPDATE
I found another more descriptive error message down below.
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'cardNumber' cannot be found on object of type '...web.form.ReceiptInquirySearchForm' - maybe not public or not valid?

How can I check for that in the code? I know sometimes it will be there, but apparently in this instance it is not.

They were doing this in Velocity like this:

<input type="hidden" name="cardNumber" value="$!receiptInquirySearchForm.cardNumber" />

The exclamation correctly handled the possible missing or null cardNumber.

Answer 1

Just as @Metroids pointed out, you are probably missing getters/setters for the field cardNumber especially a getter for it. If you have a getter for it, check that the getter follows the POJO convention and is public like so;

public int getCardNumber() { return cardNumber; }

If the spelling is not like so getCardNumber(), even though you can call the method in the controller to get the value, thymeleaf cannot do so because it relies on POJO convention to be able to call variable properties. I hope this helps.