Bean setters not invoked when no data entered in form fields

Bean setters not invoked when no data entered in form fields
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I began by coding the Emp JavaBean in the usual way. The hardcoded values are debugging.
The Problem :
If I enter data into the form fields then the JSP displays 9999 and DEFAULT. OK.
If I do not enter data into form fields or use the Delete key to remove existing data then
displayed : empNo is null
empName is null
I want my bean to validate that these mandatory fields are entered and I want to place
this logic inside my set methods.

Thank you for any help.

The JavaBean :

The Form :

The JSP :

You're submitting a form to a JSP? That's a rather 1999 thing to be doing. Best practice is to submit to a servlet controller.

Hi. I am not sure if this is going to solve your problem... try:

According to the theory, if the container cant find the bean, it will create it and execute what is inside of the body of jsp:useBean... am I right?

I believe that that is the expected (if undesirable) behavior. Better to gather the data in a servlet where you have more control.

Indeed. If you check out the setProperty tag you will find out that
"If a parameter has an empty or null value, the corresponding bean property is not set. "

An empty string counts as "empty" for purposes of this tag, and so the setter is not called.

Stefan Evans wrote:Indeed. If you check out the setProperty tag you will find out that
"If a parameter has an empty or null value, the corresponding bean property is not set. "

An empty string counts as "empty" for purposes of this tag, and so the setter is not called.

mmm now i understand. I did not know this.... thanks a lot for your answer

Thank you Jessid.
For other replies , I know about Controller servlets but I was just following examples in Bergsten's JSP book.