Accessing File Formats
How do I access the XYZ file format in java ?
Specifications for many file formats can be found at Wotsit. A large database of file extensions be found at www.file-extensions.org and dotwhat.net
An interesting article about Microsoft's binary file formats, especially DOC and XLS, is Why are the Microsoft Office file formats so complicated? (And some workarounds) It also mentions some alternatives to dealing with those formats directly.
Access
- JDBC/ODBC bridge - JDBC driver for ODBC databases, comes as part of the JDK; on Linux, you'll have to get ODBC up and running first:http://www.unixodbc.org/
- Jackcess - library to read and write MDB files
- HXTT Access - commercial pure Java JDBC driver for MS Access
CGM
- cgmva - an applet to display CGM files; comes with source code
CHM
- JChm - library to read CHM files
Excel
- Ostermiller Utils, CSVObjects, CSVBeans, opencsv, Java CSV - libraries to read and write CSV files. CSV is not as easy to read and write as it first looks - once all the special cases are considered, one might as well use a library.
- POI - library to read and write XLS files
- JExcelAPI - library to read and write XLS files
- Opinions on jExcelApi vs. POI: here and here
- jXLS - library for writing XLS files based on templates
- Java2Excel - library for creating Excel files based on Collections
- It is possible to use JDBC to read Excel files
- Obba works with Excel spreadsheets on Windows
- OpenXLS - "OpenXLS is the open source version of ExtenXLS - a Java spreadsheet SDK that allows you to read, modify and create Java Excel spreadsheets from your Java applications."
Gedcom
HDF (Hierarchical Data Format)
Image files
- ImageJ - Java image processing application and library that has plugins for lots of image file formats
- JIMI - library to read and write BMP, CUR, GIF, ICO, JPEG, PICT, PNG, PSD, Sun Raster, TGA, TIFF, XBM and XPM. There's a plugin for using JIMI with ImageJ, which also includes a couple of JIMI patches.
- GIF write, and TIFF, RAW, PNM and JPEG2000 read/write support for ImageIO
INI
- ini4j "is a simple Java API for handling configuration files in Windows .ini format."
Matlab
OpenDocument (ODF)
- basic Java code for reading ODF files is here
- ODFDOM is a Java library for accessing ODF files.
- jDocument.org has an open-source library for accessing all Open Document file types.
- Obba works with OpenOffice? spreadsheets
- Office2FO converts ODF documents to XSL-FO documents, making possible further transformations (like conversion to PDF using FOP)
Office Open XML
- These are the new XML-based Microsoft Office formats.
- OpenXML4J
- docx4j - create and edit docx documents using a JAXB content model matching the WordML schema
- Apache POI implements these formats.
OpenOffice Java API
- OpenOffice can read a number of file formats, and makes them accessible through its API. A starting point might be this article, this article and of course the OO developer site
- Some introductory information about the OO file format can be found here and here
- oooview is an OO Viewer written in Java.
- JODConverter is a Java library that uses the OO Java API to perform document conversions between any formats supported by OO
Outlook
- The Apache POI project developed some code that can read the texual contents of Outlook's MSG files. This page talks about that.
- Xena can convert multiple file formats -including MSG- to XML. Either the result of that conversion, or Xena's source code, may be helpful.
- JPST can read and extract PST files.
PDF
- PDF is a hard to read format. The best one can do is try to extract the text contained in a PDF file.
- iText - library to create PDFs; see ItextExample for a code example. The older version iText 2 (which uses a more permissive license) is also available: jar file, javadocs
- FOP - libray to create PDFs (and other formats) from XML by using XSL-FO transformations
- FlyingSaucer - library to convert CSS-styled XHTML to PDF
- PDFBox - library that can merge, split and print PDFs, extract text, create images from PDFs, encrypt/decrypt PDFs, fill in PDF forms and more
- PDF Clown - general-purpose library to read/create/modify PDF files. It features a rich multi-layered object model that allows access even to each single content stream instruction.
- JPedal - library for viewing and printing PDFs, can also extract text (how to print PDFs); commercial (the LGPL version provides PDF viewing only)
- PDFTextStream - commercial library to extract text from PDFs
- Adobe AcrobatViewer for JavaBean - freeware, library to display and print PDFs; introductory article; this library hasn't been updated in a long time and has problems displaying files that were created with recent PDF versions. Don't use this for anything new.
- PDF Renderer is a more up-to-date PDF viewer that renders using Java2D. Download, Examples, Printing PDFs
- ICEPdf is another library that can render PDFs.
- Qoppa offers numerous libraries for PDF-related tasks
- Aspose.Pdf for Java is a commercial library for reading and writing PDFs
- jPod is a rich PDF manipulation and rendering framework
PowerPoint
- The Apache POI project developed some code that can open and (to a limited extent) edit PPT files. This page talks about it.
Project
- The MPXJ library can work with several Project file formats.
PST
- LibPST is a C library that could be used through JNI.
- Xena can convert multiple file formats -including PST- to XML. Either the result of that conversion, or Xena's source code, may be helpful.
- java-libpst is a pure Java library that can access 64bit PST files.
QIF (used by Microsoft Money and Quicken)
- Buddi and Eurobudget are Java applications that can import and export QIF files (and thus contain code you may be able to use in your application). Both are licensed under the GPL.
RTF
- jRTF can create RTFs
- iText 2 can create RTFs: jar file, javadocs
- JavaCC - is a lexer/parser for which an RTF grammar is available. From that an RTF reader can be constructed.
Visio
- The Apache POI project developed some code that can read Visio files. This page talks about that.
Word
- POI - library to read and write DOC and DOCX files. It can also be used for extracting the text of a document.
- WordApi.exe is native Windows component with a Java interface, which lets you create Word documents, and alter word templates. Some impressions about it can be found here.
Something else?
If you encounter an obscure format for which no library is available, it may be feasible to create a reader for it if you have a file format description (which may be available on Wotsit, see link above). Several libraries, so-called lexers and parsers, are available that help in creating a reader, especially if the file format is ASCII, and not binary. You will need knowledge of regular expressions, though. Some file formats that have been tackled using this approach include RTF, CSV, HPGL and PBM/PGM/PPM. Lexers are easier to start with, but parsers can do more of the work for you. All these have ready-to-use examples on their web sites.
