Question

I’ve got a JSP page which contains a textbox, wrapped in a form. This form’s action is set to a servlet.

I would like to manipulate the string (from the user’s input in the textbox) before it is sent to the servlet, thus basically carrying out a simple request.setParameter call from the JSP to the servlet. Can this be done? If so how can I obtain the textbox’s value in the JSP?

<form action="MyServlet" method="post">
            <input type="text" name="txtUsername"/><br/>
            <input type="submit" value="Submit"/>
</form>

Answer 1

You cannot do this using JSP code.
Remember, a JSP is processed, outputting its contents to the browser; that’s where the JSP’s request/response cycle ends.

Your options are:

1. Using JavaScript.
2. Using a Filter: http://docs.oracle.com/javaee/5/api/javax/servlet/Filter.html