try the following code
<html:file property="imageFile1" styleClass="filebutton" />
and code for style is given below. You can put it in .css file and link in
jsp .filebutton
{
BORDER-RIGHT: #999999 1px solid;
BORDER-TOP: #999999 1px solid;
FONT-WEIGHT: normal;
FONT-SIZE: 10pt;
COLOR: #000000;
BORDER-LEFT: #999999 1px solid;
BORDER-BOTTOM: #999999 1px solid;
FONT-FAMILY: Verdana, Arial, Helvetica, sans-serif;
}