I am new to Java programming but I have some experience in programming.

<display:column titleKey="testOrder.voucher" width="110">
${testOrder.voucherNumber}
</display:column>


${testOrder.voucherNumber} prints a string made of a combination of letters and numbers (ABC1234).

I want a way to split the string ABC1234 and only print the number 1234 in the input box.
Also, I want the user to only be able to write numeric values in the input box.

Thanks for the help.