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Discover how to effectively handle large PDF document creation in Java using iText with performance tips and alternative solutions.
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Speed Up Your PDF Creation with iText: Efficient Techniques for Handling Large Records

Creating PDF files with large datasets can often be a frustrating experience, especially when performance is critical. For Java developers using the iText library, generating PDF files that contain thousands of records can lead to significant delays. This guide will explore a common performance issue faced by developers and offer effective solutions to speed up PDF generation.

The Problem: Slow PDF Creation with iText

Creating a PDF from Java objects in JSON format may seem straightforward, but it can quickly become inefficient. Imagine needing to create a PDF file with as many as 10,000 records, where each record is represented as a Java object in JSON.

Here’s a snippet of the code you may have used:

[[See Video to Reveal this Text or Code Snippet]]

The Slowdown

When running the above code, you might notice that it takes an excessive amount of time (like 80 seconds or even longer). If you modify your approach and attempt to add large amounts of JSON data in a single paragraph, you could find the process dragging on even further, potentially exceeding 2 minutes for only 200 records!

The Solution: Efficient PDF Generation Techniques

After facing similar challenges, a shift to a different library, OpenPdf, demonstrated significantly improved performance. Below, I've outlined the steps and techniques you can utilize to enhance your PDF creation time.

1. Switch to OpenPdf

OpenPdf is a Java library for creating and manipulating PDF files. In testing, I found it capable of generating a PDF file with 10,000 records in just 7 to 17 seconds, depending on the size of each record.

Here’s how to implement it:

[[See Video to Reveal this Text or Code Snippet]]

2. Keep Your Paragraphs Small

One critical observation is the size of the paragraphs you add to the PDF document. When adding data in large chunks (like a single paragraph with a massive string), the performance drastically diminishes. Instead:

Break your data into smaller pieces. Each paragraph should have a manageable length — in the example above, records range from 1 to 5 KB.

Add each record separately as a paragraph, which proves much more efficient.

3. Optimize Fonts and Styles

Also, consider the following while dealing with fonts:

Choose simpler font styles. While TIMES_ROMAN is a standard option, using HELVETICA as shown does not just save time but also enhances the look.

Consistently set the default font once before starting to add paragraphs instead of changing it repeatedly.

Conclusion

Generating PDFs with large datasets doesn't have to be slow. By switching to OpenPdf and implementing best practices like maintaining short paragraphs, you can significantly improve the performance of your PDF generation tasks.

If you're encountering sluggish performance while using iText, now you have strategies to work faster and more efficiently. Transforming how you handle PDF creation can save you valuable time, allowing you to focus on other essential aspects of your project.

Takeaway

Embrace these techniques and improve your PDF generation speed today!