1. Overview
Portable Document Format (PDF) is a common file format for documents. It’s used to distribute electronic documents that need to preserve their original format.
In this tutorial, we’ll explore two of the most popular libraries for reading PDF files in Java: Apache PDFBox and iText.
2. Setup
We’ll use Maven to manage dependencies.
Furthermore, we’ll add a sample PDF file to the project root directory. The file contains a simple phrase “Hello World!”.
Next, we’ll read the sample PDF file and test the extracted text against an expected result.
3. Using Apache PDFBox
Apache PDFBox is a free and open-source Java library for processing and manipulating PDF documents. Its capabilities include extracting text, rendering PDFs to images, and merging and splitting PDFs.
Let’s add the Apache PDFBox dependency to the pom.xml:
<dependency>
<groupId>org.apache.pdfbox</groupId>
<artifactId>pdfbox</artifactId>
<version>${pdfbox.version}</version>
</dependency>
Here’s a simple example of using Apache PDFBox to read text from a PDF file:
@Test
public void givenSamplePdf_whenUsingApachePdfBox_thenCompareOutput() throws IOException {
String expectedText = "Hello World!\n";
File file = new File("sample.pdf");
PDDocument document = PDDocument.load(file);
PDFTextStripper stripper = new PDFTextStripper();
String text = stripper.getText(document);
document.close();
assertEquals(expectedText, text);
}
In this example, we created a new instance of PDDocument to load the PDF file into the program. Then, we created a new instance of PDFTextStripper and invoked getText() to extract the text from the PDF file.
4. Using iText
iText is an open-source library for generating and using PDF files in Java. It provides a simple API for reading text from PDF files.
First, let’s include the iText dependency in the pom.xml:
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>${itextpdf.version}</version>
</dependency>
Let’s see a simple example of using the iText PDF library to extract text from a PDF file:
@Test
public void givenSamplePdf_whenUsingiTextPdf_thenCompareOutput() throws IOException {
String expectedText = "Hello World!";
PdfReader reader = new PdfReader("sample.pdf");
int pages = reader.getNumberOfPages();
StringBuilder text = new StringBuilder();
for (int i = 1; i <= pages; i++) {
text.append(PdfTextExtractor.getTextFromPage(reader, i));
}
reader.close();
assertEquals(expectedText, text.toString());
}
In this example, we created a new instance of PdfReader to open the PDF file. Then, we invoked the getNumberOfPages() method to get the number of pages of the PDF file. Finally, we looped through the pages and invoked getTextFromPage() on PdfTextExtractor to extract the content of the pages.
5. Conclusion
In this article, we learned two different ways of reading PDF files in Java. We used iText and Apache PDFBox libraries to extract text from a sample PDF file. Both libraries offer simple and effective APIs for extracting text from PDF documents.
As usual, the complete source code for the examples is available over on GitHub.
