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Home » Newsletter » August 2007

By Suryanarayan P

PDFOne Java makes it very easy to merge and split PDF documents. In this article, you will learn to perform these tasks.

Merging PDF Documents

Merging PDF documents can be performed using the merge() method of the PDFDocument class. This method takes an array list parameter containing pathnames of the files that need to be merged.

To illustrate this, I created a new PDF document “MergedDocument.pdf” by merging three PDF documents of different sizes namely “Envelope.pdf”, “ResellerLetter.pdf” and “ResellerForm.pdf”.

import java.io.IOException;
import java.util.ArrayList;

import com.gnostice.pdfone.PdfDocument;
import com.gnostice.pdfone.PdfException;
 
public class MergeDocuments {

  public static void main(String[] args) throws IOException, PdfException {
    // Load pathnames of the documents that 
    // need to be merged in a list
    ArrayList al = new ArrayList();
    al.add("Envelope.pdf");
    al.add("ResellerLetter.pdf");
    al.add("ResellerForm.pdf");
     
    // Create a document instance
    PdfDocument doc = new PdfDocument();
    // Merge documents in the list
    doc.merge(al);
     
    // Save merged documents to file
    doc.save("MergedDocument.pdf");
    doc.close();
  }
}

And, here is the result.

Splitting PDF Documents

PDFOne Java offers two ways of splitting PDF files:

• Extract a selection of pages from the original document and store it in a single output PDF document - using extractPagesTo() method of PDFDocument class.
• Divide the pages in the original document based on a number and store them in several output PDF documents - using split() method of PDFDocument class.

import java.io.IOException;

import com.gnostice.pdfone.PdfDocument;
import com.gnostice.pdfone.PdfException;
import com.gnostice.pdfone.PdfNeedFileNameHandler;
 
public class SplitDocuments implements PdfNeedFileNameHandler {
  static int iFileCounter = 1;

  // Specify an event handler that will provide the output filenames
  public void onNeedFileName(PdfDocument d, StringBuffer fileName)  {
    fileName.delete(0, fileName.length());
    fileName.append("Split_File_" + (iFileCounter++) + ".pdf");
  }
 
  public static void main(String[] args) throws IOException, PdfException {
    // Load the document that needs to be split
    PdfDocument d = new PdfDocument();
    d.load("DocumentToSplit.pdf");
     
    // Extract pages 1, 2, & 4
    d.extractPagesTo("ExtractedPages.pdf", "1-2,4");
     
    // Set PdfNeedFileNameHandler.onNeedFileName() handler, 
    // which will provide file names for the split files
    d.setOnNeedFileName(new SplitDocuments());
     
    // Split the document into 1-page documents
    d.split(1);
    
    // Close the input document    
    d.close();
  }
}

The extractPagesTo() method takes the pathname of an output file and a page range as arguments. It extracts all pages in the specified page range and saves them to the specified output file.

The split() method takes a number as argument. It begins extracting consecutive pages totaling that number into new PDF documents until all pages in the original document are exhausted. The names of the new documents are provided by the onNeedFileName method of the PdfNeedFileNameHandler interface implemented by the class calling the split() method.