How to automate PDF form-filling in Java

Question

I am doing some "pro bono" development for a food pantry near where I live. They are inundated with forms and paperwork, and I would like to develop a system that simply reads data from their MySQL server (which I set up for them on a previous project) and feeds data into PDF versions of all the forms they are required to fill out. This will help them out enormously and save them a lot of time, as well as get rid of a lot of human errors that are made when filling out these forms.

Not knowing anything about the internals of PDF files, I can foresee two avenues here:

• Harder Way: It is possible to scan a paper document, turn it into a PDF, and then have software that "fills out" the PDF simply by saying "add text except blah to the following (x,y) coordinates..."; or
• Easier Way: PDF specification already allows for the construct of "fields" that can be filled out; this way I just write code that says "add text excerpt blah to the field called *address_value*...", etc.

So my first question is: which of the two avenues am I facing? Does PDF have a concept of "fields" or do I need to "fill out" these documents by telling the PDF library the pixel coordinates of where to place data?

Second, I obviously need an open source (and Java) library to do this. iText seems to be a good start but I've heard it can be difficult to work with. Can anyone lend some ideas or general recommendations here? Thanks in advance!

Answer 1

You can easily merge data into PDF's fields using the FDF(Form Data Format) technology.

Adobe provides a library to do that : Acrobat Forms Data Format (FDF) Toolkit

Also Apache PDFBox can be used to do that.

Answer 2

Please take a look at the chapter about interactive forms in the free ebook The Best iText Questions on StackOverflow. It bundles the answers to questions such as:

• How to fill out a pdf file programatically?
• How can I flatten a XFA PDF Form using iTextSharp?
• Checking off pdf checkbox with itextsharp
• How to continue field output on a second page?
• finding out required fields to fill in pdf file
• and so on...

Or you can watch this video where I explain how to use forms for reporting step by step.

See for instance:

public void manipulatePdf(String src, String dest) throws DocumentException, IOException {     PdfReader reader = new PdfReader(src);     PdfStamper stamper = new PdfStamper(reader,             new FileOutputStream(dest));     AcroFields fields = stamper.getAcroFields();     fields.setField("name", "CALIFORNIA");     fields.setField("abbr", "CA");     fields.setField("capital", "Sacramento");     fields.setField("city", "Los Angeles");     fields.setField("population", "36,961,664");     fields.setField("surface", "163,707");     fields.setField("timezone1", "PT (UTC-8)");     fields.setField("timezone2", "-");     fields.setField("dst", "YES");     stamper.setFormFlattening(true);     stamper.close();     reader.close(); }