After we integrated
JPivot (front-end for
Mondrian) library in one of our
Struts 1.x based web application, all file uploads working fine so far, started to fail with
NullPointerException (
NPE).
JPivot request filter is configured to intercept all requests for action (e.g. *.do). I could not find direct discussion about this issue on
Google.
After debugging for few hours myself, noticed that
JPivot RequestFilter intercepts and consumes the HTTP
multipart request stream through a
MultipartEnabledRequest wrapper even before it reaches Struts controller. Therefore
FormFile object is null in
FormBean.
The simple solution that worked was to extend the
JPivot RequestFilter class and override
doFilter(), something like shown below and use this custom filter in place of default
JPivot RequestFilter.
...
import com.tonbeller.wcf.controller.RequestFilter;
/**
* This extension modifies default behavior of
JPivot controller for file uploads
* (
multipart requests) . It allows Struts layer to handle such requests rather
* than processing itself.
*
* @author
bjha*/
public class
MyJpivotFilter extends
RequestFilter {
@Override
public final void
doFilter(
ServletRequest req,
ServletResponse res,
FilterChain fc) throws
IOException,
ServletException {
if(
isMultipartRequest(
req ) ){
//let Struts handle upload
fc.
doFilter(
req, res);
return;
}
super.
doFilter(
req, res,
fc);
}
static
boolean isMultipartRequest(
ServletRequest req) {
if (
req instanceof HttpServletRequest) {
String
reqMethod = ((
HttpServletRequest)
req).
getMethod();
if (
reqMethod != null
&&
"post".equals(
reqMethod.
toLowerCase())) {
String content =
req.
getContentType();
return (
content != null
&&
content.toLowerCase().contains("
multipart/form-data"));
}
}
return false;
}
}
Another option that could work would be to configure
JPivot RequestFilter not to intercept requests for upload
URIs via
web.xml or use
commons-fileupload library to handle uploads.
