We do not provide any GUI components but you can log in to saaspose.com and use 'My Files' module to upload or manage your files. You can also build your own component and use our API to upload and process files from Saaspose, Amazon S3 and DropBox storages.
Please check attached Java code which converts all the PDF files from a specific folder. Please also note that Saaspose returns the output as a ZIP file if output format is set to HTML because there can be several support files in the HTML output. You can use the code from http://saaspose.com/docs/display/pdf/Convert+Local+PDF+File+to+HTML+without+using+Storage+%28Java+REST%29 to unzip output file and save it as HTML.
Saaspose.Pdf does not support direct conversion to EPUB, you first need to convert PDF to DOC and then use Saaspose.Words API to convert DOC to EPUB.
Please feel free to contact us in case you have further comments or questions.
Support Developer, Saaspose Sialkot Team