B4J Code Snippet Improving the speed of reading multiple sheets from an Excel workbook with jPOI5/XLUtils

Especially noticeable when reading from a not-very-small workbook, even if it just contains multiple sheets with some tens of thousands of rows.

Slow method that opens the workbook multiple times (and, I guess, reads it/interprets its XML completely each time to load it into memory):

Dim reader As XLReaderResult
reader = XL.Reader.ReadSheetByName("C:\myfile.xlsx", "", "Sheet1")
' ... your processing for Sheet1 here ...
reader = XL.Reader.ReadSheetByName("C:\myfile.xlsx", "", "Sheet2")
' ... your processing for Sheet2 here ...
reader = XL.Reader.ReadSheetByName("C:\myfile.xlsx", "", "Sheet3")
' ... your processing for Sheet3 here ...

Significantly faster method that opens the workbook only once:

Dim writer As XLWorkbookWriter = XL.CreateWriterFromTemplate("C:\myfile.xlsx", "")
Dim reader As XLReaderResult
reader = XL.Reader.SheetToResult(writer.PoiWorkbook.GetSheetByName("Sheet1"))
' ... your processing for Sheet1 here ...
reader = XL.Reader.SheetToResult(writer.PoiWorkbook.GetSheetByName("Sheet2"))
' ... your processing for Sheet2 here ...
reader = XL.Reader.SheetToResult(writer.PoiWorkbook.GetSheetByName("Sheet3"))
' ... your processing for Sheet3 here ...
writer.PoiWorkbook.Close