Finding file type XLS or XLSX using POI APIs.

[Samir Banerjee]

This one is weird but if some one can help me out with this...
There is on function in our application where we pass the excel data as byte format :

String  canParse(final byte[] templateData) {
InputStream template = template = new ByteArrayInputStream(templateData);

now depending upon the file type xls or xlsx I want to do.

POIFSFileSystem fs = new POIFSFileSystem(template);
HSSFworkbook workbook = new HSSFWorkbook(fs);

OR

XSSFworkbook  workbook = new XSSFWorkbook(template);
}

Thanks in advance.

[Rob Spoor]

An XLSX file is actually just a special ZIP file. As such, its first two bytes are always PK (0x50 and 0x4B). You can even check the source of java.util.zip.ZipInputStream how it reads the first few bytes. Check the "src.zip" file inside your JDK installation.

[Ulf Dittmer]

Also be aware that the org.apache.poi.ss package contains classes that can hide the differences between both formats. For example, WorkbookFactory.create(InputStream) returns a Workbook you can use regardless of actual file format. Much better than having to code that yourself :-)

[Samir Banerjee]

Thank you friends. Using org.apache.poi.ss package solved my problem as now I do not need to bother about the file type.