Replacing placeholders using iText in Java

Question

I have a PDF that contains placeholders like <%DATE_OF_BIRTH%>, i want to be able to read in the PDF and change the PDF placeholder values to text using iText.

So read in PDF, use maybe a replaceString() method and change the placeholders then generate the new PDF.

Is this possible?

Thanks.

Answer 1

The use of placeholders in PDF is very, very limited. Theoretically it can be done and there are some instances where it would be feasible to do what you say, but because PDF doesn't know about structure very much, it's hard:

• simply extracting words is difficult so recognising your placeholders in the PDF would already be difficult in many cases.

• Replacing text in PDF is a nightmare because PDF files generally don't have a concept of words, lines and paragraphs. Hence no nice reflow of text for example.

Like I said, it could theoretically work under special conditions, but it's not a very good solution.

What would be a better approach depends on your use case:

1) For some forms it may be acceptable to have the complete form as a background image or PDF file and then generate your text as an overlay to that background (filling in the blanks so to speak) As pointed out by Bruno and mlk in comments, in this case you can also look into using form fields which can be dynamically filled.

2) For other forms it may be better to have your template in a structured format such as XML or HTML, do the text replacement in that format and then convert it into PDF.