用java中的zxing扫描多个条形码
用java中的zxing扫描多个条形码
提问于 2014-07-22 10:33:57
我要读一下pdf417条形码。图像上通常有不止一个条形码-
这是我的密码：
InputStream in = null;
BufferedImage bfi = null;
File[] files = new File(DIR).listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
try {
System.out.println(files[i].getName());
in = new FileInputStream(files[i]);
bfi = ImageIO.read(in);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
Result result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = reader.decode(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
} catch (ChecksumException e) {
e.printStackTrace();
} catch (FormatException e) {
e.printStackTrace();
}
System.out.println(result.getBarcodeFormat());
System.out.println("Text " + result.getText());
System.out
.println("-------------------------------------------------------");
} else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}
}这有时有效，但有时不起作用，结果是空的。
我查看了zxing的javadoc，发现了一个GenericMultipleBarcodeReader。我试图在我的代码中使用，但是我做错了，因为我得到了一个NullPointerException：
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(reader);
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
}
for (int j = 0; j < result.length; j++) {
System.out.println(result[j].getBarcodeFormat());
System.out.println("Text " + result[j].getText());
}
Exception in thread "main" java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.translateResultPoints(GenericMultipleBarcodeReader.java:163)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:96)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at barcode.ZXingTest.main(ZXingTest.java:77)因此，问题是:使用GenericMultipleBarcodeReader (或其他类)扫描图像上的多个条形码更好吗?如果是这样，我如何实现？
更新：
for (int i = 0; i < files.length; i++) {
try (BufferedInputStream bfin = new BufferedInputStream(
new FileInputStream(files[i]))) {
dateiname = files[i].getName();
bfi = ImageIO.read(bfin);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(
new ByQuadrantReader(reader));
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
e.printStackTrace();
System.out.println("No result");
System.out.println("+++++++++++++++++++++++++++++++");
}
if (result != null) {
for (int j = 0; j < result.length; j++) {
System.out.println(result[j].getText());
System.out.println("+++++++++++++++++++++++++++++++");
}
}
} else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}如果我不使用ByQuadrantReader，就会得到相同的NullPointerException。我这样做，result.length有时是1(返回一个字符串)，有时我得到一个NotFoundException。
我希望这不是我代码中我看不到的愚蠢的错误.
第二版编辑：
Exception in thread "main" java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:109)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at barcode.ZXingTestMulti.main(ZXingTestMulti.java:86)第三版：
current version of code:
public static void main(final String[] args) {
BufferedImage bfi = null;
File[] files = new File(DIR).listFiles();
int counttiffs = 0;
String filename = null;
TreeMap<String, Exception> errormap = new TreeMap<String, Exception>();
int onebarcode = 0;
int twobarcodes = 0;
int threebarcodes = 0;
for (int i = 0; i < files.length; i++) {
if (files[i].isFile()) {
try (BufferedInputStream bfin = new BufferedInputStream(
new FileInputStream(files[i]))) {
filename = files[i].getName();
bfi = ImageIO.read(bfin);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (bfi != null) {
LuminanceSource ls = new BufferedImageLuminanceSource(bfi);
BinaryBitmap bmp = new BinaryBitmap(new HybridBinarizer(ls));
Reader reader = new MultiFormatReader();
GenericMultipleBarcodeReader greader = new GenericMultipleBarcodeReader(
reader);
Result[] result = null;
Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>();
decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
try {
result = greader.decodeMultiple(bmp, decodeHints);
} catch (NotFoundException e) {
errormap.put(filename, e);
} catch (NullPointerException e) {
errormap.put(filename, e);
}
if (result != null) {
switch (result.length) {
case 1:
onebarcode++;
break;
case 3:
threebarcodes++;
break;
default:
twobarcodes++;
}
try (BufferedWriter bfwr = new BufferedWriter(
new FileWriter(FILE, true))) {
bfwr.write(filename + ": number of barcodes found = "
+ result.length);
bfwr.newLine();
for (int j = 0; j < result.length; j++) {
bfwr.write(result[j].getText());
}
bfwr.newLine();
bfwr.write("---------------------------------------------------------");
bfwr.newLine();
counttiffs++;
} catch (IOException e) {
e.printStackTrace();
}
}
}
else {
System.out.println("No Buffered Image for "
+ files[i].getName());
}
}
}我使用的是核心和javase的快照3.1.1。
正如你所看到的，我需要抓住一个NPE：
java.lang.NullPointerException
at com.google.zxing.multi.GenericMultipleBarcodeReader.translateResultPoints(GenericMultipleBarcodeReader.java:163)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:96)
at com.google.zxing.multi.GenericMultipleBarcodeReader.doDecodeMultiple(GenericMultipleBarcodeReader.java:148)
at com.google.zxing.multi.GenericMultipleBarcodeReader.decodeMultiple(GenericMultipleBarcodeReader.java:65)
at zBarcodes_Test.ZXingTestMulti.main(ZXingTestMulti.java:72)和第一个一样。在您的第一次提交之后，我得到了另一行的NPE，但是现在要么我使用了错误的依赖项，要么再次发生了这种情况。
另一件事是:我扫描了大约2.500个tiff文件，每个文件上都有两个pdf417条形码，一些文件有点倾斜，有些文件质量不佳(意味着一些像素是白色的，而不是黑色的)。我总共得到了1644个错误，要么是由NotFoundException或NullPointer异常引起的。在扫描成功的948个文件中，218个result.length是1个(它只找到一个条形码)，68个文件中，result.length是3个(但它扫描了2个条形码)。
在你的经验中，当条形码不是过份直的，边缘没有什么错误，像素没有被完美打印的时候，这样的效果有多明智呢？
回答 1
Stack Overflow用户
回答已采纳
发布于 2014-07-24 11:06:39
这看起来就像一个bug，我在https://github.com/zxing/zxing/commit/e715fec42a2f8643c8f53c331f7218a1e62b0dc2中修复了它，您能通过抓取3.1.1快照来尝试修复吗？
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/24885024
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