Question

我的代码基于此 https://github.com/Betel-Flowers/BetelFlowers/blob/master/BetelFlowers-ejb/src/main/java/com/betel/flowers/pdf/util/RemoveBlankPageFromPDF.java 或这个 http://www.rgagnon.com/javadetails/java-detect-and-remove-blank-page-in-pdf.html

我正在尝试使用字节数组作为输入，将字节数组作为输出。

这是我的代码

import java.io.ByteArrayOutputStream;
import java.io.IOException;

import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.pdf.PdfCopy;
import com.lowagie.text.pdf.PdfDictionary;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfName;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.RandomAccessFileOrArray;

public class RemoveBlankPageFromPDF {

    // value where we can consider that this is a blank image
    // can be much higher or lower depending of what is considered as a blank page
    public static final int BLANK_THRESHOLD = 160;

    public static byte[] removeBlankPdfPages(byte[] fuente) throws IOException, DocumentException{
        PdfReader r = null;
        RandomAccessFileOrArray raf = null;
        Document document = null;
        PdfCopy writer = null;
        ByteArrayOutputStream archivoFinal = new ByteArrayOutputStream();

        try {
            r = new PdfReader(fuente);

            raf = new RandomAccessFileOrArray(fuente);
            document = new Document(r.getPageSizeWithRotation(1));
            writer = new PdfCopy(document,archivoFinal);
            document.open();
            PdfImportedPage page = null;

            for (int i = 1; i <= r.getNumberOfPages(); i++) {
                PdfDictionary pageDict = r.getPageN(i);
                PdfDictionary resDict = (PdfDictionary) pageDict.get(PdfName.RESOURCES);
                boolean noFontsOrImages = true;
                if (resDict != null) {
                    noFontsOrImages = resDict.get(PdfName.FONT) == null
                            && resDict.get(PdfName.XOBJECT) == null;
                }

                if (!noFontsOrImages) {
                    byte bContent[] = r.getPageContent(i, raf);
                    ByteArrayOutputStream bs = new ByteArrayOutputStream();
                    bs.write(bContent);
                    System.out.println("bs size: " + bs.size());
                    if (bs.size() > BLANK_THRESHOLD) {
                        page = writer.getImportedPage(r, i);
                        writer.addPage(page);
                    }
                }
            }
            System.out.println("Original: " + fuente.length+ " new: " + archivoFinal.toByteArray().length);
            return archivoFinal.toByteArray();
        } finally {
            if (document != null) {
                document.close();
            }
            if (writer != null) {
                writer.close();
            }
            if (raf != null) {
                raf.close();
            }
            if (r != null) {
                r.close();
            }
        }
    }
}

我的pdf被破坏后我无法打开它。

即使没有空格的pdf我也会得到不同的尺寸，它应该是相同的

Original: 95089 New: 88129

这是我的las系统输出。

我顺便使用itext 2.1.5和java 1.5。我无法升级。

Answer 1

无论如何我找到了答案。以防有人需要旧版本的itext

public static void removeBlankPdfPages(PdfReader r) throws IOException{

        PdfTextExtractor extractor = new PdfTextExtractor(r);


        List<Integer> paginas = new ArrayList<Integer>();
        for (int i = 1; i <= r.getNumberOfPages(); i++) {
            PdfDictionary pageDict = r.getPageN(i);
            PdfDictionary resDict = (PdfDictionary) pageDict.get(PdfName.RESOURCES);
            boolean noFontsOrImages = true;
            if (resDict != null) {
                noFontsOrImages = resDict.get(PdfName.FONT) == null
                        && resDict.get(PdfName.XOBJECT) == null;
            }

            if (!noFontsOrImages) {
                String textFromPage = extractor.getTextFromPage(i);

                if(textFromPage.length() >50 ){
                    paginas.add(i);
                }
            }

        }
        r.selectPages(paginas);
    }

使用itextpdf从pdf中删除空白页会破坏我的文件

1 个答案: