If you don’t like to read large amounts of text on a screen and prefer (printing on) paper, this article will show you how to use Java to automate some useful PDF manipulations. To save paper and ink/toner, my usual workflow is to remove extra pages from PDFs, then crop the text area to make it bigger, and to remove white margins. Then I merge 2 pages per sheet and I split the doc. into multiple, smaller files, to make it easier to print on both sides if the printer doesn’t support full-duplex. I chose Java and PDFBox because they are extremely fast on large files and they have a ton of options and possibilities to integrate with other projects. Create a new Java project with Maven Let's start by creating a new Java project, named , with Maven: pdf_utils mvn archetype:generate \ -DgroupId=com.pdf.pdf_utils \ -DartifactId=pdf_utils \ -DarchetypeArtifactId=maven-archetype-quickstart \ -DarchetypeVersion=1.4 \ -DinteractiveMode=false Then, open the file and add a dependency to , in the section: pdf_utils/pom.xml PDFBox dependencies <dependencies> ... <dependency> <groupId>org.apache.pdfbox</groupId> <artifactId>pdfbox</artifactId> <version>2.0.27</version> </dependency> ... </dependencies> Also change the target & source compiler versions: <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>17</source> <target>17</target> </configuration> </plugin> </plugins> Then rename the generated class to src/main/java/com/pdf/pdf_utils/App.java PDFUtils How to crop a PDF We will now develop a Java function that crops each page within a PDF document and saves the cropped content in a new PDF file. The cropping coordinates, specified in millimeters, will serve as inputs to the function. Add helper functions to convert between mm <-> units Convert mm to units Extract the doc's file name Crop each page Save the result & append "-cropped" to the ouyput file's name public String cropPDFMM(float x, float y, float width, float height, String srcFilePath) throws IOException { // helper functions to convert between mm <-> units Function<Float, Float> mmToUnits = (Float a) -> a / 0.352778f; Function<Float, Float> unitsToMm = (Float a) -> a * 0.352778f; // convert mm to units float xUnits = mmToUnits.apply(x); float yUnits = mmToUnits.apply(y); float widthUnits = mmToUnits.apply(width); float heightUnits = mmToUnits.apply(height); // extract the doc's file name File srcFile = new File(srcFilePath); String fileName = srcFile.getName(); int dotIndex = fileName.lastIndexOf('.'); String fileNameWithoutExtension = (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex); // crop each page PDDocument doc = PDDocument.load(srcFile); int nrOfPages = doc.getNumberOfPages(); PDRectangle newBox = new PDRectangle( xUnits, yUnits, widthUnits, heightUnits); for (int i = 0; i < nrOfPages; i++) { doc.getPage(i).setCropBox(newBox); } // save the result & append -cropped to the file name File outFile = new File(fileNameWithoutExtension + "-cropped.pdf"); doc.save(outFile); doc.close(); return outFile.getCanonicalPath(); } Let's test by calling it from the function: cropPDFMM main public static void main( String[] args ) { String srcFilePath = "/Users/user/.../file.pdf"; PDFUtils app = new PDFUtils(); try { ///// crop pdf float x = 18f; float y = 20f; float width = 140f; float height = 210f; String resultFilePath = app.cropPDFMM(x, y, width, height, srcFilePath); System.out.println( "Done!" ); } catch (Exception e) { System.out.println(e); } } You should see a file named in the current directory. file-cropped.pdf How to remove pages from a PDF To remove specific pages from a document, we can utilize an array of integer ranges. Each range consists of a start page and an end page ([startPage1, endPage1, startPage2, endPage2, ...]). The function iterates through each page of the document and checks if the page number falls outside of any of the specified ranges in the array. If a page is not within any range, it is appended to a new document. Add a helper function to test if a page is within a range Test each page number -> append it to a temp. doc Save the temp. doc. -> overwrite the input file public void removePages(String srcFilePath, Integer[] pageRanges) throws IOException { // a helper function to test if a page is within a range BiPredicate<Integer, Integer[]> pageInInterval = (Integer page, Integer[] allPages) -> { for (int j = 0; j < allPages.length; j+=2) { int startPage = allPages[j]; int endPage = allPages[j+1]; if (page >= startPage-1 && page < endPage) { return true; } } return false; }; File srcFile = new File(srcFilePath); PDDocument pdfDocument = PDDocument.load(srcFile); PDDocument tmpDoc = new PDDocument(); // test if a page is within a range // if not, append the page to a temp. doc. for (int i = 0; i < pdfDocument.getNumberOfPages(); i++) { if (pageInInterval.test(i, pageRanges)) { continue; } tmpDoc.addPage(pdfDocument.getPage(i)); } // save the temporary doc. tmpDoc.save(new File(srcFilePath)); tmpDoc.close(); pdfDocument.close(); } Let's test it by calling in the main function: removePages ///// remove pages app.removePages(resultFilePath, new Integer[] {1, 21, 376, 428}); It will overwrite the input (cropped) file. How to split a PDF We will now introduce a function that enables the splitting of a PDF into multiple separate PDFs, with each resulting file containing a specified number of pages. The function expects two inputs: the path to the source PDF document and the desired number of pages in each split file. Extract source file's name for each nrOfPages append them to a temporary document save the temp doc with the source file's name + index public void splitPDF(String srcFilePath, int nrOfPages) throws IOException { // extract file's name File srcFile = new File(srcFilePath); String fileName = srcFile.getName(); int dotIndex = fileName.lastIndexOf('.'); String fileNameWithoutExtension = (dotIndex == -1) ? fileName : fileName.substring(0, dotIndex); PDDocument pdfDocument = PDDocument.load(srcFile); // extract every nrOfPages to a temporary document // append an index to its name and save it for (int i = 1; i < pdfDocument.getNumberOfPages(); i+=nrOfPages) { Splitter splitter = new Splitter(); int fromPage = i; int toPage = i+nrOfPages; splitter.setStartPage(fromPage); splitter.setEndPage(toPage); splitter.setSplitAtPage(toPage - fromPage ); List<PDDocument> lst = splitter.split(pdfDocument); PDDocument pdfDocPartial = lst.get(0); File f = new File(fileNameWithoutExtension + "-" + i + ".pdf"); pdfDocPartial.save(f); pdfDocPartial.close(); } pdfDocument.close(); } Here is the full function: main() public static void main( String[] args ){ String srcFilePath = "/Users/user/pdfs/file.pdf"; PDFUtils app = new PDFUtils(); try { ///// crop pdf float x = 18f; float y = 20f; float width = 140f; float height = 210f; String resultFilePath = app.cropPDFMM(x, y, width, height, srcFilePath); ///// remove pages app.removePages(resultFilePath, new Integer[] {1, 21, 376, 428}); ///// split pages app.splitPDF(resultFilePath, 20); System.out.println( "Done!" ); } catch (Exception e) { System.out.println(e); } } Merge 2 pages per sheet (2up) This function is inspired from . https://stackoverflow.com/questions/12093408/pdfbox-merge-2-portrait-pages-onto-a-single-side-by-side-landscape-page Create a temporary document Iterate over the pages of the original doc. -> get the left & right pages Create a new "output" page with the right dimensions Append the left page at (0,0) Append the right page, translated to (left page's width, 0) Save the temp. doc -> overwrite the source file public void mergePages(String srcFilePath) throws IOException { // SOURCE: https://stackoverflow.com/questions/12093408/pdfbox-merge-2-portrait-pages-onto-a-single-side-by-side-landscape-page File srcFile = new File(srcFilePath); PDDocument pdfDocument = PDDocument.load(srcFile); PDDocument outPdf = new PDDocument(); for (int i = 0; i < pdfDocument.getNumberOfPages(); i+=2) { PDPage page1 = pdfDocument.getPage(i); PDPage page2 = pdfDocument.getPage(i+1); PDRectangle pdf1Frame = page1.getCropBox(); PDRectangle pdf2Frame = page2.getCropBox(); PDRectangle outPdfFrame = new PDRectangle(pdf1Frame.getWidth()+pdf2Frame.getWidth(), Math.max(pdf1Frame.getHeight(), pdf2Frame.getHeight())); // Create output page with calculated frame and add it to the document COSDictionary dict = new COSDictionary(); dict.setItem(COSName.TYPE, COSName.PAGE); dict.setItem(COSName.MEDIA_BOX, outPdfFrame); dict.setItem(COSName.CROP_BOX, outPdfFrame); dict.setItem(COSName.ART_BOX, outPdfFrame); PDPage newP = new PDPage(dict); outPdf.addPage(newP); // Source PDF pages has to be imported as form XObjects to be able to insert them at a specific point in the output page LayerUtility layerUtility = new LayerUtility(outPdf); PDFormXObject formPdf1 = layerUtility.importPageAsForm(pdfDocument, page1); PDFormXObject formPdf2 = layerUtility.importPageAsForm(pdfDocument, page2); AffineTransform afLeft = new AffineTransform(); layerUtility.appendFormAsLayer(newP, formPdf1, afLeft, "left" + i); AffineTransform afRight = AffineTransform.getTranslateInstance(pdf1Frame.getWidth(), 0.0); layerUtility.appendFormAsLayer(newP, formPdf2, afRight, "right" + i); } outPdf.save(srcFile); outPdf.close(); pdfDocument.close(); } Update to test it: main() ... ///// 2 pages per sheet app.mergePages(resultFilePath); ... Here is the full list of imports: package com.pdf.pdf_utils; import org.apache.pdfbox.cos.COSDictionary; import org.apache.pdfbox.cos.COSName; import org.apache.pdfbox.multipdf.LayerUtility; import org.apache.pdfbox.multipdf.Splitter; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDPage; import org.apache.pdfbox.pdmodel.common.PDRectangle; import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject; import java.awt.geom.AffineTransform; import java.io.File; import java.io.IOException; import java.util.List; import java.util.function.BiPredicate; import java.util.function.Function; The source code is available . here Also published . here
