apache-poi

Can anyone explain how to add Custom colours either using (rgb values or hex values ) to an excelsheet sheet(either in foreground or background) using Cellstyle in Apche poi to a Excelsheet(XSSF Workbook)? Setting custom colors depends on the kind of Excel file (Office Open XML format *.xlsx vs. BIFF format *.xls ). And it might be different using different versions of apache poi because of deprecation. Using Office Open XML format *.xlsx we can simply set new colors using constructor of XSSFColor . In apache poi 4.0.0 XSSFColor(byte[] rgb, IndexedColorMap colorMap) can be used.

Is there any way I can check if the file being uploaded is in excel format? I am using Apache POI library to read excel, and checking the uploaded file extension while reading the file. Code snippet for getting the extension String suffix = FilenameUtils.getExtension(uploadedFile.getName()); courtesy BalusC : uploading-files-with-jsf String fileExtension = FilenameUtils.getExtension(uploadedFile.getName()); if ("xls".equals(fileExtension)) { //rest of the code } I am sure, this is not the proper way of validation. Sample code for browse button <h:inputFileUpload id="file" value="#