HSSFSheet

HSSFSheet is a class in the Apache POI library that represents a worksheet in an HSSF workbook, the component that handles Excel 97-2003 binary files (.xls). It is a concrete implementation of the Sheet interface used by applications to interact with the contents of a sheet in an HSSFWorkbook.

From an application perspective, HSSFSheet provides access to rows and cells. You can create and retrieve rows with createRow(int) and getRow(int), and access cells through the Row and Cell interfaces to read or write values, formulas, and styles. The sheet works in tandem with the workbook’s data format and font style managers to apply consistent formatting.

In addition to basic data access, HSSFSheet supports sheet-level properties and layout features, including setting default column widths and row heights, adjusting column widths, merging cell regions, and managing page breaks and print setup. It also allows toggling display options such as gridlines and supports standard row and column iteration via methods like getFirstRowNum and getLastRowNum.

Under the hood, HSSFSheet interacts with HSSFWorkbook and BIFF8 records; it is designed for the older binary format. Writing changes to disk is performed through the HSSFWorkbook.write(OutputStream) method. Features specific to the newer OOXML format available in XSSFSheet are not provided by HSSFSheet.

HSSFSheet is used when working with .xls files in the POI ecosystem. It is part of the POI usermodel, and its methods are also accessible through the common SS API to facilitate format-agnostic code when appropriate.