Apache POI - Core Classes

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This chapter explains a few classes and methods under the Apache POI API that are critical to work on Excel files using Java programs.

Workbook

This is the super-interface of all classes that create or maintain Excel workbooks. It belongs to the org.apache.poi.ss.usermodel package. The two classes that implement this interface are as follows −

• HSSFWorkbook − This class has methods to read and write Microsoft Excel files in .xls format. It is compatible with MS-Office versions 97-2003.

• XSSFWorkbook − This class has methods to read and write Microsoft Excel and OpenOffice xml files in .xls or .xlsx format. It is compatible with MS-Office versions 2007 or later.

HSSFWorkbook

It is a high-level class under the org.apache.poi.hssf.usermodel package. It implements the Workbook interface and is used for Excel files in .xls format. Listed below are some of the methods and constructors under this class.

Class Constructors

The frequently used parameters inside these constructors are −

• directory − It is the POI filesystem directory to process from.

• fs − It is the POI filesystem that contains the workbook stream.

• preservenodes − This is an optional parameter that decides whether to preserve other nodes like macros. It consumes a lot of memory as it stores all the POIFileSystem in memory (if set).

Note − The HSSFWorkbook class contains a number of methods; however they are compatible with xls format only. In this tutorial, the focus is on the latest version of Excel file formats. Hence, the class methods of HSSFWorkbook are not listed here. If you require these class methods, then refer POI-HSSFWorkbook class API at https://poi.apache.org/apidocs/org/apache/poi/hssf/usermodel/HSSFWorkbook.html.

XSSFWorkbook

It is a class that is used to represent both high and low level Excel file formats. It belongs to the org.apache.xssf.usemodel package and implements the Workbook interface. Listed below are the methods and constructors under this class.

Class Constructors

Class Methods

For the remaining methods of this class, refer the complete API document at − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFWorkbook.html. for the complete list of methods.

Sheet

Sheet is an interface under the org.apache.poi.ss.usermodel package and it is a super-interface of all classes that create high or low level spreadsheets with specific names. The most common type of spreadsheet is worksheet, which is represented as a grid of cells.

HSSFSheet

This is a class under the org.apache.poi.hssf.usermodel package. It can create excel spreadsheets and it allows to format the sheet style and sheet data.

Class Constructors

XSSFSheet

This is a class which represents high level representation of excel spreadsheet. It is under org.apache.poi.hssf.usermodel package.

Class Constructors

Class Methods

For the remaining methods of this class, refer the complete API at − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFSheet.html.

Row

This is an interface under the org.apache.poi.ss.usermodel package. It is used for high-level representation of a row of a spreadsheet. It is a super-interface of all classes that represent rows in POI library.

XSSFRow

This is a class under the org.apache.poi.xssf.usermodel package. It implements the Row interface, therefore it can create rows in a spreadsheet. Listed below are the methods and constructors under this class.

Class Methods

For the remaining methods of this class, follow the given link https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFRow.html

Cell

This is an interface under the org.apache.poi.ss.usermodel package. It is a super-interface of all classes that represent cells in the rows of a spreadsheet.

Cells can take various attributes such as blank, numeric, date, error, etc. Cells should have their own numbers (0 based) before being added to a row.

XSSFCell

This is a class under the org.apache.poi.xssf.usermodel package. It implements the Cell interface. It is a high-level representation of cells in the rows of a spreadsheet.

Class Methods

For the remaining methods and fields of this class, visit the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFCell.html

XSSFCellStyle

This is a class under the org.apache.poi.xssf.usermodel package. It will provide possible information regarding the format of the content in a cell of a spreadsheet. It also provides options for modifying that format. It implements the CellStyle interface.

Class Constructors

Class Methods

For the remaining methods and fields in this class, go through the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFCellStyle.html

HSSFColor

This is a class under the org.apache.poi.hssf.util package. It provides different colors as nested classes. Usually these nested classes are represented by using their own indexes. It implements the Color interface.

Nested classes

All nested classes of this class are static and each class has its index. These nested color classes are used for cell formatting such as cell content, border, foreground, and background. Listed below are some of the nested classes.

Class Methods

Only one method of this class is important and that is used to get the index value.

For the remaining methods and nested classes, refer the following link − https://poi.apache.org/apidocs/org/apache/poi/hssf/util/HSSFColor.html

XSSFColor

This is a class under the org.apache.poi.xssf.usermodel package. It is used to represent color in a spreadsheet. It implements the Color interface. Listed below are some of its methods and constructors.

Class Constructors

Class Methods

For the remaining methods, visit the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFColor.html

XSSFFont

This is a class under the org.apache.poi.xssf.usermodel package. It implements the Font interface and therefore it can handle different fonts in a workbook.

Class Constructor

Class Methods

For the remaining methods, go through the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFFont.html

XSSFHyperlink

This is a class under the org.apache.poi.xssf.usermodel package. It implements the Hyperlink interface. It is used to set a hyperlink to the cell contents of a spreadsheet.

Class Methods

For the remaining methods, visit the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFHyperlink.html

XSSFCreationHelper

This is a class under the org.apache.poi.xssf.usermodel package. It implements the CreationHelper interface. It is used as a support class for formula evaluation and setting up hyperlinks.

Class Methods

For the remaining methods, refer the following link − https://poi.apache.org/apidocs/org/apache/poi/xssf/usermodel/XSSFCreationHelper.html

XSSFPrintSetup

This is a class under the org.apache.poi.xsssf.usermodel package. It implements the PrintSetup interface. It is used to set print page size, area, options, and settings.

Class Methods

For the remaining methods, visit the following link − https://poi.apache.org/apidocs/org/apache/poi/hssf/usermodel/HSSFPrintSetup.html