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Convert XML to PDF using iText in Java

In many real-world applications, there is a need to convert XML data into PDF documents. XML is a widely used format for storing and transporting data due to its structured nature, while PDF is a popular format for sharing documents as it preserves the layout across different platforms. iText is a well-known Java library that can be used to create, manipulate, and convert PDF documents. In this blog post, we will explore how to convert XML to PDF using iText in Java.

Table of Contents#

  1. Core Concepts
  2. Typical Usage Scenarios
  3. Prerequisites
  4. Code Example
  5. Common Pitfalls
  6. Best Practices
  7. Conclusion
  8. FAQ
  9. References

Core Concepts#

XML#

XML (eXtensible Markup Language) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. It uses tags to define elements and attributes to provide additional information about those elements.

PDF#

PDF (Portable Document Format) is a file format developed by Adobe that captures all the elements of a printed document as an electronic image that you can view, navigate, print, or forward to someone else.

iText#

iText is a Java library that allows developers to create, manipulate, and convert PDF documents. It provides a high-level API to work with PDF content, such as adding text, images, tables, etc.

Typical Usage Scenarios#

  1. Report Generation: Generate reports in PDF format from XML-based data sources. For example, financial reports, sales reports, etc.
  2. Document Archiving: Convert XML-based documents into PDF for long-term archiving. PDF is more stable and widely supported than XML for archival purposes.
  3. Data Sharing: Share XML data in a more presentable and secure PDF format. PDF can be password-protected and has better control over printing and editing.

Prerequisites#

  • Java Development Kit (JDK) installed on your system.
  • iText library added to your Java project. You can add it using Maven or Gradle. For Maven, add the following dependency to your pom.xml:
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itext7-core</artifactId>
    <version>7.1.15</version>
    <type>pom</type>
</dependency>

Code Example#

import com.itextpdf.html2pdf.HtmlConverter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
 
public class XmlToPdfConverter {
 
    public static void main(String[] args) {
        try {
            // Path to the XML file
            String xmlFilePath = "input.xml";
            // Path to the output PDF file
            String pdfFilePath = "output.pdf";
 
            // Convert XML to PDF
            convertXmlToPdf(xmlFilePath, pdfFilePath);
 
            System.out.println("XML converted to PDF successfully.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    public static void convertXmlToPdf(String xmlFilePath, String pdfFilePath) throws IOException {
        // Create input and output streams
        InputStream xmlInputStream = new FileInputStream(new File(xmlFilePath));
        OutputStream pdfOutputStream = new FileOutputStream(new File(pdfFilePath));
 
        // Convert XML to PDF using iText's HtmlConverter
        // Note: iText's HtmlConverter can also handle XML with proper XHTML structure
        HtmlConverter.convertToPdf(xmlInputStream, pdfOutputStream);
 
        // Close the streams
        xmlInputStream.close();
        pdfOutputStream.close();
    }
}

Explanation#

  1. Import Statements: We import necessary classes from the iText library and Java's standard I/O classes.
  2. main Method: It sets the paths for the input XML file and the output PDF file and calls the convertXmlToPdf method.
  3. convertXmlToPdf Method: It creates input and output streams for the XML and PDF files respectively. Then it uses HtmlConverter.convertToPdf method to convert the XML content to PDF. Finally, it closes the input and output streams.

Common Pitfalls#

  1. XML Structure: iText's HtmlConverter expects XML to follow a proper XHTML structure. If the XML has an incorrect structure, the conversion may fail or produce unexpected results.
  2. Encoding Issues: If the XML file has a different encoding than the default encoding of the Java environment, it may lead to character encoding problems in the generated PDF.
  3. Dependency Issues: Incorrect or outdated iText library versions can cause compilation or runtime errors.

Best Practices#

  1. Validate XML: Before conversion, validate the XML file to ensure it follows the correct XHTML structure. You can use XML validators like Xerces.
  2. Handle Encoding: Specify the correct encoding for the XML file when reading it. For example, you can use InputStreamReader with the appropriate character encoding.
  3. Keep Dependencies Updated: Regularly update the iText library to the latest stable version to avoid known bugs and security vulnerabilities.

Conclusion#

Converting XML to PDF using iText in Java is a powerful and useful technique. It allows you to leverage the structured nature of XML and the portability of PDF. By understanding the core concepts, being aware of common pitfalls, and following best practices, you can effectively convert XML data into high-quality PDF documents in your Java applications.

FAQ#

Q1: Can iText handle any type of XML?#

A1: iText's HtmlConverter works best with XML that follows a proper XHTML structure. If your XML has a custom or non-XHTML structure, you may need to pre-process it before conversion.

Q2: How can I add custom styling to the generated PDF?#

A2: You can add CSS styles to your XML file. iText's HtmlConverter will apply these styles during the conversion process.

Q3: Is iText free to use?#

A3: iText has both open-source and commercial licenses. The open-source version has certain limitations, while the commercial version offers more features and support.

References#

2025-10