我有一个大约 5 MB 的文件，我想使用 IText 读取该文件。我的目标是将这个 PDF 中的许多页面叠加到另一个 PDF 上。

这是我的代码：

try {               
    AssetManager assetManager = getActivity().getAssets();
    InputStream istr = null;
    PdfReader reader = null;
    istr =(InputStream) assetManager.open("chem.pdf");
    reader=new PdfReader(istr);  
    Document document = new Document();
    PdfWriter writer=  PdfWriter.getInstance(document, new FileOutputStream(Environment.getExternalStorageDirectory()+ "/pdfpdfpdfpdfpdf.pdf"));
    document.open();
    document.add(new Paragraph("                                                          Generated By Harshvardhan Gupta"));
    document.newPage();
    PdfContentByte canvas = writer.getDirectContent();
    PdfImportedPage page;
    //Rectangle r=document.getPageSize();
    float pos=720;
    float CurPsize=0; 
    float counter=0;
    float oldc=0;
    //r.getBottom();
    for(int m=1;m<35;m++,counter++) {
        page = writer.getImportedPage(reader, m);
        Rectangle r=reader.getPageSize(m);
        CurPsize= (r.getTop()-r.getBottom());
        pos=pos-CurPsize;
        Rectangle q=reader.getPageSize(m+1); 
        int mq=(int) (q.getTop()-q.getBottom());
        if(pos<mq+counter*25+50){
            document.newPage();
            pos=720;
            counter=0;
        }
        canvas.setTextRenderingMode(PdfContentByte.TEXT_RENDER_MODE_FILL);
        canvas.addTemplate(page, 1f, 0, 0, 1,100,pos-70-counter*25);
        BaseFont bf= BaseFont.createFont();
        canvas.setTextRenderingMode(PdfContentByte.TEXT_RENDER_MODE_FILL_STROKE);
        canvas.beginText();
        canvas.setFontAndSize(bf,14);
        canvas.setTextMatrix(75, (float) ((float) (pos-70-counter*25)-10+CurPsize));
        canvas.setLineWidth(0.5f);
        canvas.showText(m+"."+" ");
        canvas.endText();
    }
    document.close();
    writer.freeReader(reader);
    writer.close();
    reader.close();
    //spinner.setVisibility(View.INVISIBLE);
    Log.d("OK", "done");
} catch (FileNotFoundException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (DocumentException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
//spinner.setVisibility(View.INVISIBLE);

发生了相当多的事情，但我认为甚至在从资源中读取 PDF 之前就会抛出 OutOfMemoryError 。

这是完整的错误日志：

06-21 19:39:12.090: E/AndroidRuntime(6844): FATAL EXCEPTION: main
06-21 19:39:12.090: E/AndroidRuntime(6844): java.lang.OutOfMemoryError
06-21 19:39:12.090: E/AndroidRuntime(6844):     at java.io.ByteArrayOutputStream.expand(ByteArrayOutputStream.java:91)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:201)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.FlateDecode(PdfReader.java:2004)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.FlateDecode(PdfReader.java:1859)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.FilterHandlers$Filter_FLATEDECODE.decode(FilterHandlers.java:107)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.decodeBytes(PdfReader.java:2409)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.decodeBytes(PdfReader.java:2357)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.getStreamBytes(PdfReader.java:2422)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.readObjStm(PdfReader.java:1363)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.readDocObj(PdfReader.java:1305)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.readPdf(PdfReader.java:649)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:187)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:328)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:349)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.mainpackage.FragmentOne$1.onClick(FragmentOne.java:88)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.view.View.performClick(View.java:3511)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.view.View$PerformClick.run(View.java:14105)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.os.Handler.handleCallback(Handler.java:605)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.os.Handler.dispatchMessage(Handler.java:92)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.os.Looper.loop(Looper.java:137)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at android.app.ActivityThread.main(ActivityThread.java:4424)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at java.lang.reflect.Method.invokeNative(Native Method)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at java.lang.reflect.Method.invoke(Method.java:511)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:825)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:592)
06-21 19:39:12.090: E/AndroidRuntime(6844):     at dalvik.system.NativeStart.main(Native Method)

请注意，我尝试使用较小的文件（200kb）并且它有效。这是否意味着我无法使用 iText 在 Android 上读取这么大的文件？

解决方案

我的 pdf 有很多使用钢笔工具的注释。这就是造成问题的原因。我去掉了笔迹，pdf 加载得很好。