Build a Java Barcode Reader in 10 MinutesBarcodes remain a simple, reliable way to encode information for inventory, retail, logistics, and many other applications. If you need a quick, practical solution to read barcodes in Java, this guide walks you through building a functional Java barcode reader in about 10 minutes. It covers libraries, setup, sample code for images and webcam input, handling different barcode formats (1D and 2D), and tips to improve accuracy and performance.
What you’ll build
A small Java app that:
- Loads an image or captures frames from a webcam,
- Detects and decodes common barcode types (e.g., EAN-13, Code 128, QR Code),
- Prints decoded text and barcode type to the console.
Estimated time: 10 minutes (if you have Java and Maven/Gradle set up).
Tools and libraries
Use one of these proven libraries:
- ZXing (“Zebra Crossing”) — popular, open-source for 1D and 2D barcodes.
- BoofCV — powerful for computer vision, includes barcode detection.
- ZBar (via JNI/third-party wrappers) — optimized C library; less Java-native.
This guide uses ZXing for its simplicity and broad format support.
Project setup (Maven)
Create a Maven project and add ZXing dependencies. In your pom.xml include:
<dependencies> <dependency> <groupId>com.google.zxing</groupId> <artifactId>core</artifactId> <version>3.5.1</version> </dependency> <dependency> <groupId>com.google.zxing</groupId> <artifactId>javase</artifactId> <version>3.5.1</version> </dependency> </dependencies> (If you use Gradle, add equivalent dependencies to build.gradle.)
Basic barcode reading from an image
This example reads barcodes from a static image file (PNG/JPEG).
import com.google.zxing.*; import com.google.zxing.client.j2se.BufferedImageLuminanceSource; import com.google.zxing.common.HybridBinarizer; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.io.File; public class ImageBarcodeReader { public static void main(String[] args) throws Exception { if (args.length == 0) { System.out.println("Usage: java ImageBarcodeReader <image-file>"); return; } File file = new File(args[0]); BufferedImage image = ImageIO.read(file); if (image == null) { System.err.println("Could not read image: " + args[0]); return; } LuminanceSource source = new BufferedImageLuminanceSource(image); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); Reader reader = new MultiFormatReader(); try { Result result = reader.decode(bitmap); System.out.println("Decoded text: " + result.getText()); System.out.println("Barcode format: " + result.getBarcodeFormat()); } catch (NotFoundException e) { System.out.println("No barcode found in image."); } } } Run: java -cp target/yourjar.jar ImageBarcodeReader barcode.jpg
Reading multiple barcodes or detecting multiple results
ZXing’s core decode attempts a single best result. For images with several barcodes, use the MultipleBarcodeReader:
import com.google.zxing.multi.GenericMultipleBarcodeReader; import com.google.zxing.multi.MultipleBarcodeReader; // inside main after creating reader and bitmap: MultipleBarcodeReader multiReader = new GenericMultipleBarcodeReader((Reader) reader); Result[] results = multiReader.decodeMultiple(bitmap); for (Result r : results) { System.out.println(r.getBarcodeFormat() + ": " + r.getText()); } Real-time webcam scanning
For a quick webcam-based scanner, use the javacv/JavaCV or OpenCV Java bindings to capture frames and feed them to ZXing. Example using OpenCV (assumes OpenCV Java is set up):
import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.videoio.VideoCapture; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import com.google.zxing.*; import com.google.zxing.client.j2se.BufferedImageLuminanceSource; import com.google.zxing.common.HybridBinarizer; import java.awt.image.DataBufferByte; public class WebcamBarcodeReader { static { System.loadLibrary(Core.NATIVE_LIBRARY_NAME); } public static BufferedImage matToBufferedImage(Mat mat) { int type = BufferedImage.TYPE_BYTE_GRAY; if (mat.channels() > 1) { type = BufferedImage.TYPE_3BYTE_BGR; } int bufferSize = mat.channels() * mat.cols() * mat.rows(); byte[] b = new byte[bufferSize]; mat.get(0, 0, b); BufferedImage image = new BufferedImage(mat.cols(), mat.rows(), type); final byte[] targetPixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData(); System.arraycopy(b, 0, targetPixels, 0, b.length); return image; } public static void main(String[] args) { VideoCapture camera = new VideoCapture(0); if (!camera.isOpened()) { System.err.println("Cannot open camera"); return; } Mat frame = new Mat(); Reader reader = new MultiFormatReader(); while (true) { if (!camera.read(frame)) break; BufferedImage image = matToBufferedImage(frame); LuminanceSource source = new BufferedImageLuminanceSource(image); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); try { Result result = reader.decode(bitmap); System.out.println("Decoded: " + result.getText() + " (" + result.getBarcodeFormat() + ")"); // optionally break after success break; } catch (NotFoundException e) { // continue scanning } } camera.release(); } } Handling multiple barcode formats
Configure hints to prioritize formats you expect and improve speed:
import java.util.EnumSet; import java.util.Map; import java.util.HashMap; import com.google.zxing.DecodeHintType; import com.google.zxing.BarcodeFormat; Map<DecodeHintType,Object> hints = new HashMap<>(); hints.put(DecodeHintType.POSSIBLE_FORMATS, java.util.Arrays.asList(BarcodeFormat.QR_CODE, BarcodeFormat.EAN_13, BarcodeFormat.CODE_128)); hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE); Reader reader = new MultiFormatReader(); ((MultiFormatReader)reader).setHints(hints); Tips to improve accuracy and speed
- Preprocess: convert to grayscale, increase contrast, denoise, deskew.
- Resize large images down to a reasonable resolution (keeping barcode readable).
- Use TRY_HARDER for difficult images, but it’s slower.
- Limit POSSIBLE_FORMATS when you only expect certain types.
- For low-light or motion blur, capture several frames and use the sharpest.
Common pitfalls
- Blurry or low-resolution images often fail — ensure clear focus and sufficient DPI.
- Barcodes near image edges or partially occluded may not decode.
- Reflection on glossy surfaces can confuse detection — try changing angle or lighting.
- Different libraries vary in supported formats and robustness.
Where to go next
- Add a GUI (Swing/JavaFX) to show camera preview and overlay detected barcode bounding boxes.
- Integrate with a database or inventory system to look up decoded codes.
- Use BoofCV if you need advanced image processing and detection capabilities.
This guide gave a compact, practical route to a working Java barcode reader using ZXing: project setup, image and webcam examples, handling multiple formats, and tips for reliability. Follow the sample code and adapt hints/preprocessing to your environment for best results.
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