4 Ways to Convert Java HTML to PDF

Converting HTML to PDF using Java is a common requirement in many applications, from generating reports to archiving web pages. The process involves transforming the structure and content of an HTML document into a static PDF file, preserving formatting and layout. This conversion can be achieved through various libraries and techniques, each with its own advantages and disadvantages. Understanding these different approaches allows developers to choose the method that best suits their specific needs and project requirements. In this article, we’ll explore 4 Ways to Convert Java HTML to PDF, providing code examples and outlining the pros and cons of each method.

1. Using iText

iText is a popular and powerful Java library for creating and manipulating PDF documents. It offers extensive features for handling complex layouts, fonts, and images. While iText is versatile, it can have a steeper learning curve compared to some simpler libraries. Here’s a basic example of how to convert HTML to PDF using iText:

// Import necessary iText classes
import com.itextpdf.html2pdf.HtmlConverter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class HtmlToPdfIText {

public static void main(String[] args) throws IOException {
// Path to the HTML file
String htmlFilePath = “input.html”;

// Path to the output PDF file
String pdfFilePath = “output_itext.pdf”;

// Convert HTML to PDF
try (FileInputStream htmlFile = new FileInputStream(htmlFilePath);
FileOutputStream pdfFile = new FileOutputStream(pdfFilePath)) {
HtmlConverter.convertToPdf(htmlFile, pdfFile);
}

System.out.println(“HTML converted to PDF using iText successfully!”);
}
}

Pros: Robust, feature-rich, excellent control over PDF generation. Cons: Can be complex, requires understanding of iText’s API, licensing considerations for commercial use.

2. Using Flying Saucer (XHTML Renderer)

Flying Saucer, also known as XHTML Renderer, is a Java library designed specifically for rendering XML/XHTML content as PDFs. It relies heavily on CSS for styling and layout, making it a good choice if your HTML is well-structured and styled with CSS. It is often simpler to use than iText for basic HTML to PDF conversions.

// Import necessary Flying Saucer classes
import org.w3c.dom.Document;
import org.xhtmlrenderer.pdf.ITextRenderer;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;

public class HtmlToPdfFlyingSaucer {

public static void main(String[] args) throws Exception {
// Path to the HTML file
String htmlFilePath = “input.html”;

// Path to the output PDF file
String pdfFilePath = “output_flyingsaucer.pdf”;

// Create a DocumentBuilder
DocumentBuilder builder = DocumentBuilderFactory.newInstance.newDocumentBuilder;
Document document = builder.parse(new File(htmlFilePath));

// Create an ITextRenderer
ITextRenderer renderer = new ITextRenderer;
renderer.setDocument(document, null);
renderer.layout;

// Create an OutputStream
try (OutputStream os = new FileOutputStream(pdfFilePath)) {
renderer.createPDF(os);
}

System.out.println(“HTML converted to PDF using Flying Saucer successfully!”);
}
}

Pros: Relatively simple to use, good CSS support, suitable for well-structured XHTML. Cons: Less powerful than iText for advanced PDF manipulation, may have limitations with complex HTML or unsupported CSS.

3. Using Apache PDFBox

Apache PDFBox is another popular Java library for working with PDF documents. While it’s primarily used for manipulating existing PDFs, it can also be used to create PDFs from scratch, including converting HTML content. This often involves parsing the HTML and then manually constructing the PDF structure using PDFBox’s API.

This method is often more complex than using iText or Flying Saucer for HTML conversion directly, as it requires more manual handling of the PDF structure and content. Therefore, it’s usually more suited for situations where you need fine-grained control over the PDF creation process or where you’re already using PDFBox for other PDF-related tasks.

4. Using Open HTML to PDF

Open HTML to PDF is a relatively new open-source Java library that aims to provide a streamlined and modern approach to HTML to PDF conversion. It builds upon Flying Saucer and iText, offering improved CSS support and better handling of modern HTML features. It is designed to be easier to use than some of the older libraries. Here’s how you can use it:

// Import necessary Open HTML to PDF classes
import com.openhtmltopdf.pdfboxout.PdfRendererBuilder;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStream;
public class HtmlToPdfOpenHtml {

public static void main(String[] args) throws Exception {
// Path to the HTML file
String htmlFilePath = “input.html”;
// Path to the output PDF file
String pdfFilePath = “output_openhtml.pdf”;

// Create an OutputStream
try (OutputStream os = new FileOutputStream(pdfFilePath)) {
// Build the PDF renderer
PdfRendererBuilder builder = new PdfRendererBuilder;
builder.withUri(new File(htmlFilePath).toURI.toString);
builder.toStream(os);
builder.run;
}
System.out.println(“HTML converted to PDF using Open HTML to PDF successfully!”);
}
}

Pros: Modern approach, improved CSS support, potentially easier to use than iText. Cons: Relatively new, may have fewer community resources compared to established libraries.

Comparison Table

Choosing the right method depends on the complexity of your HTML, the level of control you need over the PDF generation process, and your familiarity with the different libraries. Ultimately, understanding the nuances of each approach will help you effectively implement 4 Ways to Convert Java HTML to PDF in your Java applications, ensuring you produce high-quality, accurate, and visually appealing PDF documents.