I've been researching ways to write tags to my images similar to how Windows Live Photo Gallery works. I've played with several different libraries (metadata-extractor,jhead,jheader,sanselan) but have only really found Sanselan to accomodate writing the data back in that I need.
I followed Apache's WriteExifMetadataExample<http://commons.apache.org/proper/commons-imaging//xref-test/org/apache/sanselan/sampleUsage/WriteExifMetadataExample.html> to a T & It worked flawlessly for updating the GPS data and Aperture. I then attempted to modify the example to update EXIF_TAG_XPKEYWORDS rather thanEXIF_TAG_APERTURE_VALUE. In the above-linked example, I replaced the TiffOutputField.create line with the following: String currentTagsAsString = new String((byte[]) jpegMetadata.findEXIFValue(ExifTagConstants.EXIF_TAG_XPKEYWORDS).getValue());System.out.println("current tags: '" + currentTagsAsString + "'");String newTag = "h e l l o";String newTagsAsString = currentTagsAsString.trim() + " ; " + newTag + " ";System.out.println("new desired tags: '" + newTagsAsString + "'");TiffOutputField keywords = new TiffOutputField(ExifTagConstants.EXIF_TAG_XPKEYWORDS, FieldType.FIELD_TYPE_BYTE, newTagsAsString.length(), newTagsAsString.getBytes()); exifDirectory.removeField(ExifTagConstants.EXIF_TAG_XPKEYWORDS); exifDirectory.add(keywords); Other than commenting out the aperature and GPS update code, the rest I left alone. I will admit the format of the byte array has me a little confused so that may very well be the issue. I get no warnings/errors/etc. The process completes normally but the new Image file does not contain the updated tags. Why does the new image not contain the updated tags? Is there an easier/better way? I have found that my string formatting was a little off in my example above. The actual encoding of the original byte array does not include space characters, but instead the '0' byte. I have adjusted the code accordingly still with no luck. Also, this E-mail is a direct copy of an existing stack overflow question<http://stackoverflow.com/questions/15593707/writing-exif-xpkeywords-with-sanselan>which I posed and has yet to yield any help. Feel free to answer the stackoverflow question instead. Randy Aldrich http://randyaldrich.net
