Open xls and xlsx with Apache POI
I want to open my excel file with Apache POI.
I don't know if a file is xls or xlsx. I have only something like this:
InputStream myExcelFile = new ByteArrayInputStream(file.getData());
This way I can open xls file:
HSSFWorkbook hsf = new HSSFWorkbook(myxls);
And this way I can open xlsx file:
XSSFWorkbook xsf = new XSSFWorkbook(myxls);
How can I open both types of files if I don't know format?
This will do the work:
Workbook wb = WorkbookFactory.create(myExcelFile);
Then you can check the exact type created by the factory:
if (wb instanceof HSSFWorkbook) {
// do whatever
} else if (wb instanceof SXSSFWorkbook) {
// do whatever
} else if (wb instanceof XSSFWorkbook) {
// do whatever
}
Anyway if you want to know the real type of the file before using it you can use Apache Tika.
Workbook wb = WorkbookFactory.create(myExcelFile);
if (wb instanceof HSSFWorkbook) {
// do whatever
} else if (wb instanceof SXSSFWorkbook) {
// do whatever
} else if (wb instanceof XSSFWorkbook) {
// do whatever
}
The aforementioned approach will work.
But incase you are dealing with large files, there is a possibility that you will get File as ByteArayInputStream . In this case, the bellow approach shall work.
ByteArayInputStream bais = new ByteArrayInputStream(file.getData());
if(bais != null && POIFSFileSystem.hasPOIFSHeader(bais)) {
System.out.println(".xls extention excel file");
//do whatever
}
else if(bais != null && POIXMLDocument.hasOOXMLHeader(bais)) {
System.out.println(".xlsx extention excel file");
//do whatever
}
else {
//wrong file format. throw exception.
}
You can let POI do the job for you, by using WorkbookFactory to automatically have the file extension detected opened for you.
Workbook w = WorkbookFactory.create(new File("hello.xls"));
Of course, you can use Apache Tika to detect the file format for you!
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