在PDF中提取嵌入的附件

Question

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import com.itextpdf.text.pdf.PRStream;
import com.itextpdf.text.pdf.PdfArray;
import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfString;

public class extractAttachments{

public extractAttachments(String src, String dir) throws IOException {

    File folder = new File(dir);
       folder.mkdirs();
       PdfReader reader = new PdfReader(src);
       PdfDictionary root = reader.getCatalog();
       PdfDictionary names = root.getAsDict(PdfName.NAMES);
       PdfDictionary embedded = names.getAsDict(PdfName.EMBEDDEDFILES);
       PdfArray filespecs = embedded.getAsArray(PdfName.NAMES);
       for (int i = 0; i < filespecs.size(); ) {
         extractAttachment(reader, folder, filespecs.getAsString(i++),
         filespecs.getAsDict(i++));
       }
     }

    protected void extractAttachment(PdfReader reader, File dir, PdfString name, PdfDictionary filespec)
       throws IOException {
       PRStream stream;
       FileOutputStream fos;
       String filename;
       PdfDictionary refs = filespec.getAsDict(PdfName.EF);
       for (PdfName key : refs.getKeys()) {
         stream = (PRStream)PdfReader.getPdfObject(refs.getAsIndirectObject(key));
         filename = filespec.getAsString(key).toString();
         fos = new FileOutputStream(new File(dir, filename));
         fos.write(PdfReader.getStreamBytes(stream));
         fos.flush();
         fos.close();
       }
     }
  }

我已尝试使用上述代码从PDF中提取嵌入式附件。但它不适用于具有wordDocument的PDF。我正在使用itext5.It正在为具有文本文档的PDF工作。可能是什么问题？