custom output file extension of jasper server

[zol777]

here is my requirement:

generate a CSV report in jasper server(version 5.5.0) but output file should be ended with .txt

I have take a look of the following article

/documentation/jasperreports-server-ultimate-guide/v55/adding-custom-export-channels

but no idea how to rewrite a output file name.

By review source code of jasperreport and found a class called net.sf.jasperreports.engine.export.JRAbstractCsvExporter and actual export a report with custom file name.

However it does have a outputstream onlyduring export but without any file name during processing its exportReport method.

Does any one has anyidea that i should change those source code of jasper server to fulfill my requirement?