Reading QRCode with Zxing in Java

问题:

Some questions about using Zxing...

I write the following code to read barcode from an image:

public class BarCodeDecode 
{
    /**
     * @param args
     */
    public static void main(String[] args) 
    {
        try
        {
            String tmpImgFile = "D:\\FormCode128.TIF";

            Map<DecodeHintType,Object> tmpHintsMap = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);
            tmpHintsMap.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
            tmpHintsMap.put(DecodeHintType.POSSIBLE_FORMATS, EnumSet.allOf(BarcodeFormat.class));
            tmpHintsMap.put(DecodeHintType.PURE_BARCODE, Boolean.FALSE);

            File tmpFile = new File(tmpImgFile);
            String tmpRetString = BarCodeUtil.decode(tmpFile, tmpHintsMap);
            //String tmpRetString = BarCodeUtil.decode(tmpFile, null);
            System.out.println(tmpRetString);
        }
        catch (Exception tmpExpt)
        {
            System.out.println("main: " + "Excpt err! (" + tmpExpt.getMessage() + ")");
        }
        System.out.println("main: " + "Program end.");
    }

}

public class BarCodeUtil 
{
    private static BarcodeFormat DEFAULT_BARCODE_FORMAT = BarcodeFormat.CODE_128;

    /**
      * Decode method used to read image or barcode itself, and recognize the barcode,
      * get the encoded contents and returns it.
      * @param whatFile image that need to be read.
      * @param config configuration used when reading the barcode.
      * @return decoded results from barcode.
      */
     public static String decode(File whatFile, Map<DecodeHintType, Object> whatHints) throws Exception 
     {
         // check the required parameters
         if (whatFile == null || whatFile.getName().trim().isEmpty())
             throw new IllegalArgumentException("File not found, or invalid file name.");
         BufferedImage tmpBfrImage;
         try 
         {
             tmpBfrImage = ImageIO.read(whatFile);
         } 
         catch (IOException tmpIoe) 
         {
             throw new Exception(tmpIoe.getMessage());
         }
         if (tmpBfrImage == null)
             throw new IllegalArgumentException("Could not decode image.");
         LuminanceSource tmpSource = new BufferedImageLuminanceSource(tmpBfrImage);
         BinaryBitmap tmpBitmap = new BinaryBitmap(new HybridBinarizer(tmpSource));
         MultiFormatReader tmpBarcodeReader = new MultiFormatReader();
         Result tmpResult;
         String tmpFinalResult;
         try 
         {
             if (whatHints != null && ! whatHints.isEmpty())
                 tmpResult = tmpBarcodeReader.decode(tmpBitmap, whatHints);
             else
                 tmpResult = tmpBarcodeReader.decode(tmpBitmap);
             // setting results.
             tmpFinalResult = String.valueOf(tmpResult.getText());
         } 
         catch (Exception tmpExcpt) 
         {
             throw new Exception("BarCodeUtil.decode Excpt err - " + tmpExcpt.toString() + " - " + tmpExcpt.getMessage());
         }
         return tmpFinalResult;
    }
}

I try to read the following two images that contains code128 and QRCode.

It can work for the code128 but not for the QRCode. Any one knows why...

回答1:

Curiously your code works for me, but I had to remove the follow hint.

tmpHintsMap.put(DecodeHintType.PURE_BARCODE, Boolean.FALSE);

When my image is not pure barcode, this hint broke my result.

Thank you!

回答2:

Please go through this link for complete Tutorial. The author of this code is Joe. I have not developed this code, so I am just doing Copy paste to make sure this is available in case link is broken.

The author is using ZXing(Zebra Crossing Library) you can download it from here, for this tutorial.

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();
  }
}

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>

回答3:

This Code worked for me.

public static List<string> ScanForBarcodes(string path)
{
  return ScanForBarcodes(new Bitmap(path));
}

public static List<string> ScanForBarcodes(Bitmap bitmap)
{
  // initialize a new Barcode reader.
  BarcodeReader reader = new BarcodeReader
  {
    TryHarder = true, // TryHarder is slower but recognizes more Barcodes
    PossibleFormats = new List<BarcodeFormat> // in the ZXing There is an Enum where all supported barcodeFormats were contained
    {
      BarcodeFormat.CODE_128, 
      BarcodeFormat.QR_CODE,
      //BarcodeFormat. ... ;
    }
  };
  return reader.DecodeMultiple(bitmap).Select(result => result.Text).ToList(); // return only the barcode string.
                                                                               // If you want the full Result use: return reader.DecodeMultiple(bitmap);
}

Did you use this (ZXing.Net) Lib?