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我試圖解決使用java，iText和Java高級圖像庫的問題。我的軟件系統使用ghostscript來創建PDF文件中的JPG縮略圖等。然而，在CentOS 5.x上，ghostscript的最高版本是8.7，其中有一個已知問題，即無法處理包含JPEG 2000圖像的PDF文件。我的計劃是首先掃描文件，看它是否包含jpeg2000圖像（我已經找出了這部分）;如果是，則使用iText和Java Advanced Imaging庫（包含jpeg2000讀取&編寫編解碼器）將包含的jpeg2000文件轉換爲常規jpeg文件&，然後將新的PDF文件傳遞給ghostscript。下面的代碼試圖這樣做，但會導致另一個包含jpeg2000文件的文件。任何幫助，將不勝感激。iText PDF;如何將jpeg2000轉換爲使用Java的jpg
public class ImageReplacer{
public static void main(String [] args){
try{
String RESULT = "";
PdfReader reader = new PdfReader("pdf_containing_jpeg2000_images.pdf");
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
MyImageRenderListener listener = new MyImageRenderListener(RESULT);
MyImageConverterListener clistener = new MyImageConverterListener(RESULT);
clistener.setReader(reader);
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
parser.processContent(i, clistener);
}
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("out.pdf"));
stamper.close();
}catch(Exception e){
e.printStackTrace();
}
}
}
class MyImageConverterListener implements RenderListener {
protected String path = "";
protected PdfReader reader;
public MyImageConverterListener(String path) {
this.path = path;
}
public void beginTextBlock() { }
public void endTextBlock() { }
public void renderImage(ImageRenderInfo renderInfo) {
try {
PdfImageObject image = renderInfo.getImage();
PdfName filter = (PdfName)image.get(PdfName.FILTER);
if (PdfName.JPXDECODE.equals(filter)) {
if(image.getDictionary().isStream()){
BufferedImage bi = image.getBufferedImage();
if (bi == null) return;
int width = (int)bi.getWidth();
int height = (int)bi.getHeight();
ByteArrayOutputStream imgBytes = new ByteArrayOutputStream();
ImageIO.write(bi, "JPG", imgBytes);
PRStream stream = new PRStream(reader,imgBytes.toByteArray());
stream.clear();
stream.setData(imgBytes.toByteArray(), false, PRStream.NO_COMPRESSION);
stream.put(PdfName.TYPE, PdfName.XOBJECT);
stream.put(PdfName.SUBTYPE, PdfName.IMAGE);
stream.put(new PdfName("foo"+Math.random()), new PdfName("bar"+Math.random()));
stream.put(PdfName.FILTER, PdfName.DCTDECODE);
stream.put(PdfName.WIDTH, new PdfNumber(width));
stream.put(PdfName.HEIGHT, new PdfNumber(height));
stream.put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
stream.put(PdfName.COLORSPACE, PdfName.DEVICERGB);
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void renderText(TextRenderInfo renderInfo) { }
public void setReader(PdfReader r){
reader = r;
}
}