How to Work with PDF File Operations in Java

Concatenating PDF Files

Use PdfFileEditor.concatenate() to merge multiple PDF files into one output file. Pass an array of input paths and the target output path:

PdfFileEditor editor = new PdfFileEditor();
String[] inputs = {"part1.pdf", "part2.pdf", "part3.pdf"};
editor.concatenate(inputs, "merged.pdf");

Extracting a Page Range

Extract a contiguous range of pages with start and end page numbers (1-indexed). The extracted pages are written to a new file:

PdfFileEditor editor = new PdfFileEditor();
// Extract pages 2 through 5 (1-indexed)
editor.extract("source.pdf", 2, 5, "extracted.pdf");

Splitting into Individual Pages

Split a document so each page becomes a separate file. The output directory must already exist before calling this method:

PdfFileEditor editor = new PdfFileEditor();
editor.splitToPages("document.pdf", "output_dir/");

Resizing Page Content

Scale content within existing page boundaries using ContentsResizeParameters. Specify the left margin, content width, right margin, top margin, content height, and bottom margin as percentages — they must sum to 100 in each dimension:

try (Document doc = new Document("input.pdf")) {
    PdfFileEditor editor = new PdfFileEditor();
    ContentsResizeParameters params = new ContentsResizeParameters(
        ContentsResizeValue.percents(10),  // left margin
        ContentsResizeValue.percents(80),  // content width
        ContentsResizeValue.percents(10),  // right margin
        ContentsResizeValue.percents(10),  // top margin
        ContentsResizeValue.percents(80),  // content height
        ContentsResizeValue.percents(10)   // bottom margin
    );
    editor.resizeContents(doc, params);
    doc.save("resized.pdf");
}

Making a Booklet

Impose pages in booklet print order so the document prints correctly when folded. This reorders and pairs pages appropriately for duplex printing:

PdfFileEditor editor = new PdfFileEditor();
editor.makeBooklet("input.pdf", "booklet.pdf");