For normal HTML input tag,disabling autocomplete is simple as given below:
Whe
Autocomplete attribute is not passed through to the rendered HTML by the tag.
You can do so by writing your own custom tag that extends the tag to accept the autocomplete attribute and pass it through to the rendered tag.
check these links ::
Struts 2 + Disable Form Autocomplete
http://www.coderanch.com/t/54020/Struts/form-input-tags-turning-autocomplete