FileUpload with Richfaces

The other day I had an assignment to write a CSV upload and download interface for a JSF (Richfaces) based web application. On first sight, that isn't a really tricky task since it was realised many times before by a lot of people - including me. Therefore I was quite confident to implement that feature quite quickly ... until it came to the point where I tried out what I implemented. Unfortunately, the file was not uploaded although my code wrote the correct filename to the log output. This is my sourcecode:

public void uploadListener(final UploadEvent uploadEvent) {
UploadItem uploadItem = uploadEvent.getUploadItem();
String fileName = uploadItem.getFileName();
String csvFile = new String(uploadItem.getData());
...
}

The method signature follows the requirements set by richfaces in order for a method to receive incoming upload events. Usually the upload item variable should contain all required information, especially the required file data.

The reason why the upload item is not filled as expected, is the AJAX filter option createTempFile which is set to true by default. Under these circumstances the uploaded file data will not be made available to the upload item variable, but is written into a temporary file on disk. To change this behavior, its necessary to switch the config option of org.ajax4jsf.Filter to true in the web.xml.