How to Merge Multiple PDFs into One in Java

#tutorial #java #pdf #programming

When you need to print multiple PDF files constantly, merging them into one file is a great way to simplify the printing process and save time. In addition, merging PDF files with related content also helps us store and manage documents more easily. Next, I will show you how to merge multiple PDF files into one using a PDF library in Java.

Step 1: Tools

In this tutorial, we will use the following libraries and programs.

IntelliJ IDEA 2018
Free Spire.PDF for Java

This is a totally independent Java PDF library, which doesn’t require Adobe Acrobat or other software installed on system. But this is a free version product and only supports merging PDF files within 10 pages. If you want to merge more pages, you can choose Spire.PDF for Java and apply a 30-days free license.

Step 2: Import JAR file to your project

Download Free Spire.PDF for Java and unzip it.
Create a new project in IntelliJ IDEA and open it.
Click “File”- “Project Structure” - “Modules” - “Dependencies” in turn.
Choose the “JARs or Directories” under the right green plus, and find the “Spire.Pdf.jar” in the lib folder of the downloaded file.

Step 3: Sample Code

import com.spire.pdf.FileFormat;
import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfDocumentBase;

public class test {
    public static void main(String[] args) {

        //Get the paths of the PDFs to be merged
        String[] files = new String[] {
                "C:\\Users\\Administrator\\Desktop\\Sample1.pdf",
                "C:\\Users\\Administrator\\Desktop\\Sample2.pdf",
                "C:\\Users\\Administrator\\Desktop\\Sample3.pdf"};

        //Merge these files
        PdfDocumentBase doc = PdfDocument.mergeFiles(files);

        //Save the result file
        doc.save("C:\\Users\\Administrator\\Desktop\\MergeFiles.pdf", FileFormat.PDF);
    }
}