XSSFWorkbook takes a lot of time to load

Question

I am using the following code:

File file = new File(\"abc.xlsx\");
InputStream st = new FileInputStream(file);
XSSFWorkbook wb = new XSSFWorkbook(st);


        

Answer 1

First up, don't load a XSSFWorkbook from an InputStream when you have a file! Using an InputStream requires buffering of everything into memory, which eats up space and takes time. Since you don't need to do that buffering, don't!

If you're running with the latest nightly builds of POI, then it's very easy. Your code becomes:

File file = new File("C:\\D\\Data Book.xlsx");
OPCPackage opcPackage = OPCPackage.open(file);
XSSFWorkbook workbook = new XSSFWorkbook(opcPackage);

Otherwise, it's very similar:

File file = new File("C:\\D\\Data Book.xlsx");
OPCPackage opcPackage = OPCPackage.open(file.getAbsolutePath());
XSSFWorkbook workbook = new XSSFWorkbook(opcPackage);

Answer 2

Consider using the Streaming version of POI. This will load a subset of the file into memory as needed. It is the recommended method when dealing with large files.

POI SXSSF