java - 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);

The xlsx file itself has 25,000 rows and each row has content in 500 columns. During debugging, I saw that the third row where I create a XSSFWorkbook, it takes a lot of time (1 hour!) to complete this statement.

Is there a better way to access the values of the original xlsx file?

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);