log4j:WARN No appenders could be found for logger (org.apache.pdfbox.util.ResourceLoader).
log4j:WARN Please initialize the log4j system properly.
This message means that you need to configure the log4j logging system. See the log4j documentation for more information.
PDFBox comes with a sample log4j configuration file. To use it you set a system property like this
java -Dlog4j.configuration=log4j.xml org.apache.pdfbox.ExtractText <PDF-file> <output-text-file>
If this is not working for you then you may have to specify the log4j config file using a URL path, like this:
log4j.configuration=file:///<path to config file>
No! Only one thread may access a single document at a time. You can have multiple threads each accessing their own PDDocument object.
You need to call close() on the PDDocument inside the finally block, if you don't then the document will not be closed properly. Also, you must close all PDDocument objects that get created. The following code creates two PDDocument objects; one from the "new PDDocument()" and the second by the load method.
PDDocument doc = new PDDocument();
doc = PDDocument.load( "my.pdf" );
if( doc != null )
Text extraction from a pdf document is a complicated task and there are many factors involved that effect the possibility and accuracy of text extraction. It would be helpful to the PDFBox team if you could try a couple things.
This is because the characters in a PDF document can use a custom encoding instead of unicode or ASCII. When you see gibberish text then it probably means that a meaningless internal encoding is being used. The only way to access the text is to use OCR. This may be a future enhancement.
This probably means that the "Resources" directory is not in your classpath. The Resources directory is included in the PDFBox jar so this is only a problem if you are building PDFBox yourself and not using the binary.
PDF documents have certain security permissions that can be applied to them and two passwords associated with them, an user password and an owner password. If the "cannot extract text" permission bit is set then you need to decrypt the document with the owner password in order to extract the text.
Not really, for a couple reasons.