Sheet id would be null

[zhan-ge]

Invoke sheet.openStream() would throw an error:

org.dhatim.fastexcel.reader.ExcelReaderException: Sheet#0 'my_sheet_name' is missing an entry in workbook rels (for id: 'null')
	at org.dhatim.fastexcel.reader.OPCPackage.getSheetContent(OPCPackage.java:193)
	at org.dhatim.fastexcel.reader.ReadableWorkbook.openStream(ReadableWorkbook.java:147)
	at org.dhatim.fastexcel.reader.Sheet.openStream(Sheet.java:56)
	at org.dhatim.fastexcel.reader.Sheet.read(Sheet.java:60)
        .......

Then I debug into the stack, find the sheet's id property is null.

The dependency version is 0.12.14.