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Generate and Recognize QR Codes in Java (Simple Tutorial)

In today’s fast-changing business and technology landscape, QR codes have become synonymous with fast and efficient information transfer. From logistics tracking and mobile payments to product authentication and social media sharing, QR codes are everywhere. They greatly simplify user operations and improve the efficiency of information interaction. For Java developers, seamlessly integrating QR code generation and recognition into applications has become a common requirement. However, with the wide variety of third-party libraries available and potential implementation complexities, developers often need a solution that is both powerful and easy to use.

This article introduces Spire.Barcode for Java , a powerful tool that helps you easily tackle QR code generation and recognition challenges in Java applications. We will walk you through how to use Spire.Barcode for Java, step by step, to implement these core features in your Java programs and enhance your applications.

Preparation: Add Spire.Barcode for Java Library

Spire.Barcode for Java is a comprehensive, high-performance barcode library that supports generating and recognizing multiple 1D and 2D barcodes, including QR codes. With its ease of use, rich feature set, and excellent compatibility, it is an ideal choice for Java developers working with barcodes.

Integrating Spire.Barcode for Java into your project is straightforward. If you use Maven to manage dependencies, simply add the dependency to your project configuration file.

For Maven projects:

Add the following content to your pom.xml file:

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.barcode</artifactId>
        <version>5.1.11</version>
    </dependency>
</dependencies>
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For non-Maven projects:

If you don’t use Maven, you can download the JAR package from the Spire.Barcode for Java official website and manually add it to your project’s build path.

Part 1: Generate QR Codes with Java

Generating QR codes with Spire.Barcode for Java is straightforward. You can easily set the content, error correction level, size, and color of the QR code, and save it in various image formats.

Here’s a complete Java example showing how to generate a QR code containing specific text and save it as a PNG image:

import com.spire.barcode.BarCodeGenerator;
import com.spire.barcode.BarcodeSettings;
import com.spire.barcode.BarCodeType;
import com.spire.barcode.QRCodeECL; // Import error correction level enum

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class GenerateQrCode {
    public static void main(String[] args) {
        // Create BarcodeSettings object to configure QR code parameters
        BarcodeSettings settings = new BarcodeSettings();

        // Set QR code content
        settings.set2DData("https://www.e-iceblue.com");

        // Set barcode type to QR code
        settings.setType(BarCodeType.QR_Code);

        // Set QR code error correction level (default Low; options: Medium, Quartile, High)
        settings.setQRCodeECL(QRCodeECL.High);

        // Set width and height (in pixels)
        settings.setX(3); // Module size, affects overall dimensions
        settings.setBarHeight(90); // Overall height, combined with X and data size determines final size

        // Show border
        settings.hasBorder(true);

        // Create BarCodeGenerator object
        BarCodeGenerator generator = new BarCodeGenerator(settings);

        // Generate QR code image
        BufferedImage qrCodeImage = generator.generateImage();

        // Save QR code image to file
        try {
            File outputfile = new File("GeneratedQrCode.png");
            ImageIO.write(qrCodeImage, "PNG", outputfile);
            System.out.println("QR code successfully generated at " + outputfile.getAbsolutePath());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
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In this code:

  • We used settings.set2DData() to define the content encoded in the QR code.
  • settings.setType(BarCodeType.QR_Code) specifies that the barcode type is QR code.
  • settings.setQRCodeECL() lets you set the error correction level; higher levels improve recognition even if the code is partially damaged.
  • settings.setX() and settings.setBarHeight() control the module size and overall dimensions.
  • Finally, ImageIO.write() saves the generated BufferedImage as a PNG file.

Part 2: Recognize QR Codes with Java

Recognizing QR codes from images is another strong feature of Spire.Barcode for Java. It can efficiently extract encoded data from various image formats.

Here’s an example that shows how to load a QR code image and read its content:

import com.spire.barcode.BarcodeScanner;
import com.spire.barcode.BarCodeType;
import com.spire.barcode.BarCodeData;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class ReadQrCode {
    public static void main(String[] args) {
        // Assume we already have a QR code image file named "GeneratedQrCode.png"
        File qrCodeFile = new File("GeneratedQrCode.png");

        if (!qrCodeFile.exists()) {
            System.out.println("QR code image does not exist. Please generate it first.");
            return;
        }

        try {
            // Load image from file
            BufferedImage image = ImageIO.read(qrCodeFile);

            // Use BarcodeScanner to recognize barcodes in the image
            // Specifying BarCodeType.QR_Code improves efficiency and accuracy
            BarCodeData[] barCodeData = BarcodeScanner.scan(image, BarCodeType.QR_Code);

            // Iterate through recognition results
            if (barCodeData != null && barCodeData.length > 0) {
                for (BarCodeData data : barCodeData) {
                    System.out.println("Recognized QR code content: " + data.getBarCodeText());
                    System.out.println("Recognized QR code type: " + data.getBarCodeType());
                }
            } else {
                System.out.println("No QR code detected in the image.");
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
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In this example:

  • We first load the QR code image using ImageIO.read().
  • The core recognition method is BarcodeScanner.scan(image, BarCodeType.QR_Code). Passing BarCodeType.QR_Code helps focus on QR codes only, which improves efficiency and accuracy when images contain multiple barcode types.
  • The result is an array of BarCodeData objects, each containing recognized barcode data such as content and type. We retrieve the actual content with data.getBarCodeText().
  • Spire.Barcode for Java can recognize multiple QR codes in a single image and return all results.

Conclusion

With this detailed tutorial, you’ve learned how to use Spire.Barcode for Java to easily generate and recognize QR codes in your Java applications. Thanks to its powerful features, simple API, and excellent performance, Spire.Barcode for Java is an ideal choice for developers handling barcode-related tasks. It not only simplifies development but also ensures efficient and reliable results.

QR code technology will continue expanding its applications in the future, serving as a vital bridge between the digital and physical worlds. Now, you have the tools to leverage Java and Spire.Barcode for Java to build smarter, more connected applications.

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