我通过分别插入2种条形码QRCode和Code128来创建PDF。
现在我的问题是如何首先提取条形码图像，然后从这些图像中提取文本， 请帮我这个，我尝试了谷歌2天，但没有找到合适的方式。
我正在使用itextpdf-5.5.8版本。
答案 0 :(得分：1)
我也在研究一种类似的项目，但它在.NET中。我正在为第二个问题提供一个可选的解决方案，即从图像中读取条形码。您可以使用 ZXing 来解码条形码。下面是伪代码，你必须在函数中传递图像路径：
static void ScanBarCode(string FileName) {
System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(FileName);
try {
BarcodeReader reader = new BarcodeReader { AutoRotate = true, TryHarder = true };
Result result = reader.Decode(bitmap);
string decodedData = result.Text;
Console.WriteLine(result.ToString());
} catch {
throw new Exception("Cannot decode the Barcode code");
}
}
答案 1 :(得分：0)
以前我评论Code128 Barcode Image的一个技巧是没有让鼠标点击选择pdf，作为QRCode。
所以，我将Code128 Barcode图像存储为File在tmp文件夹中，之后我从文件中插入了这些图像，通过这样做，我得到Barcode Image鼠标点击完成图像选择javaxt.io.Image api。
以下是代码时间如何在Code128 Barcode Image中插入PDF -
private static void insertBAR(PdfContentByte cb, PdfPTable table, String text, int colspan, com.itextpdf.text.Font font){
Barcode128 code128 = new Barcode128();
code128.setBaseline(-1);
code128.setSize(16f);
//code128.setBarHeight(16f);
code128.setCode(text.trim());
code128.setCodeType(Barcode128.CODE128);
Image code128Image = code128.createImageWithBarcode(cb, new BaseColor(0, 47, 47), null);
java.awt.Image awtImage = code128.createAwtImage(new Color(0, 47, 47), Color.WHITE);
//java.awt.Image awtImage = code128.createAwtImage(Color.BLACK, Color.WHITE);
//Initialising a 6+ (width and height)size of BufferedImage to put the Barcode Image in center
BufferedImage bi = new BufferedImage(awtImage.getWidth(null)+6, awtImage.getHeight(null)+6, BufferedImage.TYPE_INT_ARGB);
Graphics2D gd = bi.createGraphics();
gd.setColor(Color.WHITE);
gd.fillRect(0, 0, bi.getWidth(), bi.getHeight());
//drawing the Barcode Image in center of BufferedImage Rect.
gd.drawImage(awtImage, 3, 3, null);
gd.dispose();
File imgFile = new File(OneMethod.getElementosPath() + "/db/tmp/Img" + (++shortCount) + ".png");
try {
javaxt.io.Image img = new javaxt.io.Image(bi);
img.saveAs(imgFile);
code128Image = Image.getInstance(imgFile.getAbsolutePath());
} catch (BadElementException | IOException ex) {
ex.printStackTrace();
}
PdfPCell cell = new PdfPCell();
cell.setMinimumHeight(35f);
cell.setHorizontalAlignment(Element.ALIGN_LEFT);
cell.setVerticalAlignment(Element.ALIGN_MIDDLE);
cell.setPadding(2f);
cell.setColspan(colspan);
cell.addElement(code128Image);
//cell.setImage(code128Image);
table.addCell(cell);
}
现在如何首先使用Barcode Image提取iText以及稍后使用String api从这些图片中检索zxing值
private void readAndValidateContents(){
if(externalLOB.size() == 2){
try {
PdfReader reader = new PdfReader(externalLOB.get(0).getAbsolutePath());
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
//Trying to Extract Images to a tmp folder
ImageRenderListener listener = new ImageRenderListener(OneMethod.getElementosPath() + "/db/tmp/Img%s.%s");
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
parser.processContent(i, listener);
}
//Retrieving String values from images extracted to tmp folder
ArrayList<String> ary = OneMethod.decodeBarcodes();
//Extracting String values from PDF Page using iText API
String[] contents = (PdfTextExtractor.getTextFromPage(reader, 1)).split("\n");
externalKey.clear();
System.out.println("\n\n");
short line = 0;
for(String str : contents){
System.out.println(line++ + str);
}
String tempVal = ary.get(0);
String[] split = tempVal.split("\n");
tempVal = split[0];
tempVal = tempVal.substring(0, tempVal.indexOf("."));
System.out.println("\n\n" + tempVal + "\n\n");
if(contents[4].equals(tempVal)){ //comparing qr bar code file name with pdf text file name
System.out.println("Something XYZ....Here...Done...")
}else{
System.err.println("Possibilities for File Interruption, File different of requested...");
}
} catch (StringIndexOutOfBoundsException spiobe){
System.err.println("File different of requested...");
} catch (IOException ioe) {
ioe.printStackTrace();
} catch (Exception ex){
ex.printStackTrace();
} finally{
OneMethod.clearDirectory(OneMethod.getElementosPath() + "/db/tmp/");
}
}
}
class OneMethod {
static synchronized ArrayList<String> decodeBarcodes(){
ArrayList<String> ary = new ArrayList<String>();
short suffix = 1;
File imageFile = null;
outer:
while(true){
if(++suffix > 5) //Starting to read the Img with Suffix 2 i.e. Img2.jpg
break outer;
inner:
while(true){
try{
InputStream barCodeInputStream;
imageFile = new File(OneMethod.getElementosPath()
+ "/db/tmp/Img" + suffix + (suffix != 2 ? ".png" : ".jpg"));
if(imageFile.exists() && imageFile.isFile()){
barCodeInputStream = new FileInputStream(imageFile.getAbsolutePath());
BufferedImage barCodeBufferedImage = ImageIO.read(barCodeInputStream);
//Using zxing-core-3.2.0 with collaborating the old 1.3 version com.google.zxing.client.j2se package inside.
//So doing above action you will get the BufferedImageLuminanceSource class which is now not available in new versions.
LuminanceSource source = new BufferedImageLuminanceSource(barCodeBufferedImage);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Reader reader = new MultiFormatReader();
Result result = reader.decode(bitmap);
System.out.println(suffix + " value is : " + result.getText());
ary.add(result.getText());
}else{
System.out.println(imageFile.getAbsolutePath() + " path is not available...");
}
break inner;
} catch(FileNotFoundException | NullPointerException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
} catch (NotFoundException | ChecksumException | FormatException ex) {
ex.printStackTrace();
}
}
}
return ary;
}
static synchronized void clearDirectory(final String dirPath){
new Thread(new Runnable(){
public void run(){
try{
File directory = new File(dirPath);
if(directory.isDirectory() == true)
try {
File[] files = directory.listFiles();
for(File file : files){
FileUtils.deleteQuietly(file);
Thread.sleep(100);
if(file.exists())
FileUtils.forceDeleteOnExit(file);
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}catch(InterruptedException exp){
exp.printStackTrace();
}
}
}).start();
}
}
class ImageRenderListener implements RenderListener {
/**
* Creates a RenderListener that will look for images.
*/
public ImageRenderListener(String path) {
this.path = path;
tempCount = 0;
}
/**
* @see com.itextpdf.text.pdf.parser.RenderListener#beginTextBlock()
*/
public void beginTextBlock() {}
/**
* @see com.itextpdf.text.pdf.parser.RenderListener#endTextBlock()
*/
public void endTextBlock() {}
/**
* @see com.itextpdf.text.pdf.parser.RenderListener#renderImage(
* com.itextpdf.text.pdf.parser.ImageRenderInfo)
*/
public void renderImage(ImageRenderInfo renderInfo) {
//public void renderImage(InlineImageInfo renderInfo) {
try {
String filename;
FileOutputStream os;
PdfImageObject image = renderInfo.getImage();
if (image == null) return;
filename = String.format(path, ++tempCount, image.getFileType());
os = new FileOutputStream(filename);
os.write(image.getImageAsBytes());
os.flush();
os.close();
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
/**
* @see com.itextpdf.text.pdf.parser.RenderListener#renderText(
* com.itextpdf.text.pdf.parser.TextRenderInfo)
*/
public void renderText(TextRenderInfo renderInfo) {}
}