Java ApachePDFBox 2可视签名在同一页面上，第二个签名不可见

PDDocument document = new PDDocument();

PDPage page = new PDPage();

PDSignatureField signatureField1 = new PDSignatureField(document);
PDSignatureField signatureField2 = new PDSignatureField(document);

PDAppearanceDictionary appearance1 = new PDAppearanceDictionary();
PDAppearanceStream appearanceStream1 = new PDAppearanceStream(document);
appearance1.setNormalAppearance(appearanceStream1);

PDRectangle rect1 = new PDRectangle(100, 100, 200, 50); // 签名框的位置和大小
appearanceStream1.setBBox(rect1);
appearanceStream1.setMatrix(new AffineTransform());
PDAnnotationWidget widget1 = signatureField1.getWidgets().get(0);
widget1.setRectangle(rect1);
widget1.setAppearance(appearance1);

PDAppearanceDictionary appearance2 = new PDAppearanceDictionary();
PDAppearanceStream appearanceStream2 = new PDAppearanceStream(document);
appearance2.setNormalAppearance(appearanceStream2);
PDRectangle rect2 = new PDRectangle(100, 200, 200, 50); // 第二个签名框的位置和大小
appearanceStream2.setBBox(rect2);
appearanceStream2.setMatrix(new AffineTransform());
PDAnnotationWidget widget2 = signatureField2.getWidgets().get(0);
widget2.setRectangle(rect2);
widget2.setAppearance(appearance2);

page.getAnnotations().add(signatureField1.getWidgets().get(0));
page.getAnnotations().add(signatureField2.getWidgets().get(0));

document.addPage(page);

document.save("path/to/output.pdf");