import com.itextpdf.kernel.pdf.PdfPage; //导入依赖的package包/类
/**
 * Extract annotations from given PDF document.
 * @param pdfDocument PDF document.
 * @return Extracted annotations.
 */
protected AnnotatedDocument extractAnnotations(PdfDocument pdfDocument) {
    AnnotatedDocument document = new AnnotatedDocument();
    PdfDocumentInfo pdfInfo = pdfDocument.getDocumentInfo();
    document.setTitle(pdfInfo.getTitle());
    document.setSubject(pdfInfo.getSubject());
    document.setAuthor(pdfInfo.getAuthor());
    List<String> keywords = convertToKeywords(pdfInfo.getKeywords());
    document.setKeywords(keywords);

    List<Annotation> annotations = new LinkedList<>();
    for (int i = 1; i <= pdfDocument.getNumberOfPages(); i++) {
        PdfPage page = pdfDocument.getPage(i);
        for (PdfAnnotation pdfAnnotation : page.getAnnotations()) {
            Annotation annotation = convertAnnotation(pdfAnnotation);
            if (annotation != null) {
                annotations.add(annotation);
            }
        } //
    } //
    document.setAnnotations(annotations);

    return document;
}
 

import com.itextpdf.kernel.pdf.PdfPage; //导入依赖的package包/类
@Override
public void handleEvent(Event event) {
    PdfDocumentEvent docEvent = (PdfDocumentEvent) event;
    PdfDocument pdfDoc = docEvent.getDocument();
    PdfPage page = docEvent.getPage();
    PdfCanvas canvas = new PdfCanvas(page.newContentStreamBefore(),
            page.getResources(), pdfDoc);
    Rectangle area = page.getPageSize();
    new Canvas(canvas, pdfDoc, area)
            .add(images.get(offset));
    offset++;
}