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Apache POI

Developer(s)	Apache Software Foundation
Stable release	5.3.0 / July 2, 2024; 5 months ago (2024-07-02)
Repository	POI Repository
Written in	Java
Operating system	Cross-platform
Type	API to access Microsoft Office formats
License	Apache License 2.0
Website	poi.apache.org

Apache POI, a project run by the Apache Software Foundation, and previously a sub-project of the Jakarta Project, provides pure Java libraries for reading and writing files in Microsoft Office formats, such as Word, PowerPoint and Excel.

History and roadmap

The name was originally an acronym for "Poor Obfuscation Implementation", referring humorously to the fact that the file formats seemed to be deliberately obfuscated, but poorly, since they were successfully reverse-engineered. This explanation – and those of the similar names for the various sub-projects – were removed from the official web pages in order to better market the tools to businesses who would not consider such humor appropriate. The original authors (Andrew C. Oliver and Marc Johnson) also noted the existence of the Hawaiian poi dish, made of mashed taro root, which had similarly derogatory connotations.

Office Open XML support

POI supports the ISO/IEC 29500:2008 Office Open XML file formats since version 3.5. A significant contribution for OOXML support came from Sourcesense, an open source company which was commissioned by Microsoft to develop this contribution. This link spurred controversy, some POI contributors questioning POI OOXML patent protection regarding Microsoft's Open Specification Promise patent license.

Architecture

The Apache POI project contains the following subcomponents (meaning of acronyms is taken from old documentation):

• POIFS (Poor Obfuscation Implementation File System) – This component reads and writes Microsoft's OLE 2 Compound document format. Since all Microsoft Office files are OLE 2 files, this component is the basic building block of all the other POI elements. POIFS can therefore be used to read a wider variety of files, beyond those whose explicit decoders are already written in POI.
• HSSF (Horrible SpreadSheet Format) – reads and writes Microsoft Excel (XLS) format files. It can read files written by Excel 97 onwards; this file format is known as the BIFF 8 format. As the Excel file format is complex and contains a number of tricky characteristics, some of the more advanced features cannot be read.
• XSSF (XML SpreadSheet Format) – reads and writes Office Open XML (XLSX) format files. Similar feature set to HSSF, but for Office Open XML files.
• HPSF (Horrible Property Set Format) – reads "Document Summary" information from Microsoft Office files. This is essentially the information that one can see by using the File|Properties menu item within an Office application.
• HWPF (Horrible Word Processor Format) – aims to read and write Microsoft Word 97 (DOC) format files. This component is in initial stages of development.
• XWPF (XML Word Processor Format) – similar feature set to HWPF, but for Office Open XML files.
• HSLF (Horrible Slide Layout Format) – a pure Java implementation for Microsoft PowerPoint files. This provides the ability to read, create and edit presentations (though some things are easier to do than others)
• XSLF (Open Office XML Slideshow Format)
• HDGF (Horrible DiaGram Format) – an initial pure Java implementation for Microsoft Visio binary files. It provides an ability to read the low level contents of the files.
• HPBF (Horrible PuBlisher Format) – a pure Java implementation for Microsoft Publisher files.
• HSMF (Horrible Stupid Mail Format) – a pure Java implementation for Microsoft Outlook MSG files.
• DDF (Dreadful Drawing Format) – a package for decoding the Microsoft Office Drawing format.
• XDDF (XML Dreadful Drawing Format)

The HSSF component is the most advanced feature of the library. Other components (HPSF, HWPF, and HSLF) are usable, but less full-featured.

The POI library is also provided as a Ruby or ColdFusion extension.

There are modules for Big Data platforms (e.g. Apache Hive/Apache Flink/Apache Spark), which provide certain functionality of Apache POI, such as the processing of Excel files.

Version history

See also

• Open Packaging Conventions
• Office Open XML software

References

1. "History of Changes". Retrieved October 28, 2024.
2. ^ Sundaram, Elango (22 March 2004), "Excelling in Excel with Java", JavaWorld, retrieved 2020-07-21
3. POI homepage from October 2004, Coyote Song, archived from the original on October 15, 2004, showing original explanations for naming.
4. SourceSense
5. McDougall, Paul (26 March 2008). "Microsoft Eyes Open Source Components for Office 2007". InformationWeek. Retrieved 2020-07-21.
6. Oliver, Andrew C. (27 March 2008), "Rejection of any ENCUMBERED Microsoft Donation to POI", POI development mailing list archives, retrieved 2020-07-21
7. ^ "POI API Documentation". Poi.apache.org. Retrieved March 7, 2019.
8. "POI-HPBF - Java API To Access Microsoft Publisher Format Files". Poi.apache.org. Retrieved March 7, 2019.
9. Codeplex NPOI, Microsoft, archived from the original on March 28, 2012
10. POI-HSMF, Apache, archived from the original on August 7, 2011, retrieved July 31, 2011
11. POI-HSSF, Apache
12. POI-HWPF, Apache
13. POI-HSLF, Apache
14. POI-Ruby, Apache
15. "HadoopOffice for Hive/Flink/Spark". Github.com. July 19, 2018. Retrieved March 7, 2019.
16. "Spark Excel". Github.com. Retrieved March 7, 2019.

External links

• Official website

• Apache Software Foundation projects
• Microsoft Office-related software
• Java platform
• Java (programming language) libraries
• Cross-platform free software