Java QR Code

Quick Response Code (QR Code) is a two-dimensional matrix like barcode, designed by a subsidiary of Toyota to mark their vehicles for tracking in their manufacturing facilities. This is nothing but a type of barcode.

The four standard modes of data for creating QR code is numeric, alphanumeric, byte / binary and Kanji. There are extensions to these standard types available, using which custom data also can be coded.

So why is it popular? QR code can store more volume of data in small area compared to the standard barcode formats. Any place where the barcodes are being used can be replace by QR codes.

QR Code
Can you scan and comment on what is in this picture?

This became easily popular because of the advent of mobile apps that can be used as a QR code scanner to read the information in QR codes. You can see advertisements in newspapers having QR codes. It may contain product information, price detail, web url, etc. If you have a smartphone with iOS or Android then you can install a QR Code app easily in a minute and scan all those codes to read the information.

Some general uses of QR codes are,

  • contact information
  • calendar event
  • URL
  • GEO location
  • website authentication
  • credit card information
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Java API for QR Code

ZXing ("Zebra Crossing") is the popular API for QR code processing in Java. Its library has multiple components and we will be using the ‘core’ for QR code creation in our Java example. Following code is example to create a QR code image and read information from a QR code image.

QR Code Write and Read Program in Java

package com.javapapers.java;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.imageio.ImageIO;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

public class QRCode {

	public static void main(String[] args) throws WriterException, IOException,
			NotFoundException {
		String qrCodeData = "Hello World!";
		String filePath = "QRCode.png";
		String charset = "UTF-8"; // or "ISO-8859-1"
		Map<EncodeHintType, ErrorCorrectionLevel> hintMap = new HashMap<EncodeHintType, ErrorCorrectionLevel>();
		hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);

		createQRCode(qrCodeData, filePath, charset, hintMap, 200, 200);
		System.out.println("QR Code image created successfully!");

		System.out.println("Data read from QR Code: "
				+ readQRCode(filePath, charset, hintMap));

	}

	public static void createQRCode(String qrCodeData, String filePath,
			String charset, Map hintMap, int qrCodeheight, int qrCodewidth)
			throws WriterException, IOException {
		BitMatrix matrix = new MultiFormatWriter().encode(
				new String(qrCodeData.getBytes(charset), charset),
				BarcodeFormat.QR_CODE, qrCodewidth, qrCodeheight, hintMap);
		MatrixToImageWriter.writeToFile(matrix, filePath.substring(filePath
				.lastIndexOf('.') + 1), new File(filePath));
	}

	public static String readQRCode(String filePath, String charset, Map hintMap)
			throws FileNotFoundException, IOException, NotFoundException {
		BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(
				new BufferedImageLuminanceSource(
						ImageIO.read(new FileInputStream(filePath)))));
		Result qrCodeResult = new MultiFormatReader().decode(binaryBitmap,
				hintMap);
		return qrCodeResult.getText();
	}
}

QR Code Write and Read Program Output

QR Code Output

Maven dependency for the ZXing QR Code library:

<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>core</artifactId>
	<version>2.2</version>
</dependency>

<dependency>
	<groupId>com.google.zxing</groupId>
	<artifactId>javase</artifactId>
	<version>2.2</version>
</dependency>
            

This Core Java tutorial was added on 15/10/2013.

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41 comments on “Java QR Code

  1. Your sample project works superb! Thanks for this nice tutorial. I learned this new today :-)

  2. Interesting!

    Happy to see this article.

    Thank You!

  3. Came across new article today! Simple and Easy explaination. Thanks Joe!

  4. Hi Joe,

    Nice example.Do you have the knowledge about capcha.Now a days in so many websites we are asking for capcha.What is use of it and how it will be helpful or exactly its purpose.

  5. Thank You Joe. You are a gem to the society.

  6. Hi,

    I put zxing.jar (version 2.2) in my libraries on exclipse, but I have an error in this 2 lines:

    BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new BufferedImageLuminanceSource(ImageIO.read(new FileInputStream(filePath)))));
    Result qrCodeResult = new MultiFormatReader().decode(binaryBitmap, hintMap);

    BufferedImageLuminanceSource and HybridBinarizer are not recognized.
    Can you help me please

    • You need to add two jar files and they are,

      1. core-2.2.jar
      2. javase-2.2.jar

      They can be downloaded from zxing maven repository or it is there in the example project I have done along with the tutorial.

      As of now, the jar files are not provided by zxing along with their regular downloads. They provide only the source files. Either we need to compile the jar from their project or download it from the maven repository.

      • Works good.

        Thank you Joe and keep up the good work!

  7. Thanks Joe, with this article I came to know what exactly QR is.

  8. Very nice article. Learnt something new today..Thanks Joe

  9. Hi Joe , very nice tutorial. I looking for a java library for sending sms from usb GSM modem via GSM Network. I need it for my accademic project .Can you help me or suggest me please ? Thanks.

  10. Hi Joe,

    Excellent one. From this example, whatever we written in the image, we can able to read. Can you please let us know how to read data from the existing/written by others QR images.

    • If you have the QR image is printed in paper, then we can read it using mobile apps. There are free apps available for Android, iOS and other mobile OS.

  11. Very Nice article… keep up the good work of being blessed to all javaites.

  12. it’s nice tutorial it helped me… thanks.

  13. Thanks a lot Joe.. I could generate QR codes of different colours easily. Could you please tell how to display this in a webpage. i.e) everytime we hit submit a different QR code should be dynamically generated.

  14. good tutorial, with sample code and dependencies info.

    Thanks

  15. Very good code.

    I hope to make a Java mobile app from this for Nokia.

    Thanks

  16. very useful code, especially when u are in a hurry like in a hackathon :)
    Tx

  17. By This Tutorial I learn something Different today. Thanks a lot sir…

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