如何在 iText 签名印章中添加自定义字段？

Question

我有一个简单的签名方法可以很好地签署 PDF 文档，它使用显示名称、位置、日期和原因的默认图章签署文档。

现在我的经理问我是否可以在上面再添加一个字段。假设这是一个“电子邮件”字段，因为我没有被告知他们想要什么。

我尝试搜索并应用我找到的东西，但没有任何效果。

另外，有人问我是否可以删除/隐藏这 4 个默认字段（日期、原因等）的标签，但我无法做到，也找不到任何相关信息，我没有不知道是否真的可以定制。

在这里，我将展示她的签名过程是如何工作的。在 middel 中，我在 iText 网站上找到了一些代码，并尝试使用它来添加“新字段”，但没有显示与默认标记不同的任何结果。

public String signPdfFirstTime(String src, String dest, PrivateKey pk, Certificate[] chain, String providerName, String conteudoBase64, X509Certificate cert) throws IOException, DocumentException, GeneralSecurityException {

    byte[] content = Base64.decode(conteudoBase64);

    FileOutputStream fos = new FileOutputStream(path + File.separator + src);
    fos.write(content );
    fos.close();

    File f = new File(path + File.separator + src);

    FileInputStream in = new FileInputStream(f);

    PdfReader reader = new PdfReader(in);

    FileOutputStream os = new FileOutputStream(path + File.separator + dest);
    PdfStamper stamper = PdfStamper.createSignature(reader, os, '\0');
    // Creating the appearance
    PdfSignatureAppearance appearance = stamper.getSignatureAppearance();
    appearance.setReason("SOME REASON");
    appearance.setLocation("SOMEWHERE");
    //  appearance.getAppearance().curveFromTo(98, 120, 46, 94);
    Rectangle rectangle = new Rectangle(0, 0, 500, 70);

    appearance.setVisibleSignature(rectangle, 1, "SIGNATURE");

    //Here I trid to add fields to the stamp
    //NOT WORKING AS I EXPECTED...
    PdfWriter writer = stamper.getWriter();
    PdfFormField field = PdfFormField.createEmpty(writer);
    field.setFieldName("TEST 1111");
    TextField name = new TextField(writer,rectangle, "TEST 2222");
    PdfFormField personal_name = name.getTextField();
    field.addKid(personal_name);
    TextField password = new TextField(writer, rectangle, "password");
    PdfFormField personal_password = password.getTextField();
    field.addKid(personal_password);
    stamper.addAnnotation(field, 1);

    appearance.setCertificate(cert);
    // Creating the signature
    ExternalSignature pks = new PrivateKeySignature(pk, DigestAlgorithms.SHA256, providerName);
    ExternalDigest digest = new BouncyCastleDigest();
    List<CrlClient> crlList = new ArrayList<CrlClient>();
    crlList.add(new CrlClientOnline());

    LtvVerification v = stamper.getLtvVerification();

    OcspClient ocspClient = new OcspClientBouncyCastle();

    String url = CertificateUtil.getCRLURL(cert);
    CertificateFactory cf = CertificateFactory.getInstance("X.509");

    X509CRL crl = (X509CRL) cf.generateCRL(new URL(url).openStream());
    System.out.println("CRL valid until: " + crl.getNextUpdate());
    System.out.println("Certificate revoked: " + crl.isRevoked(chain[0]));

    if (crl.isRevoked(chain[0])) {

        throw new GeneralSecurityException("CERTIFICADO REVOGADO!");
    }
    else {
        MakeSignature.processCrl(cert, crlList);

        MakeSignature.signDetached(appearance, digest, pks, chain, null, null, null, 0, CryptoStandard.CMS);
        os.close();
        byte[] b = this.read(f);
        return Base64.encodeBytes(b);
    }
}

Answer 1

PdfSignatureAppearance 类允许您设置自动生成外观的文本

/**
 * Sets the signature text identifying the signer.
 * @param text the signature text identifying the signer. If <CODE>null</CODE> or not set
 * a standard description will be used
 */
public void setLayer2Text(String text)

使用的字体可以设置使用

/**
 * Sets the n2 and n4 layer font. If the font size is zero, auto-fit will be used.
 * @param layer2Font the n2 and n4 font
 */
public void setLayer2Font(Font layer2Font)

如果您想进一步控制外观，可以检索第 2 层模板并在其上设计任何您想要的内容。

/**
 * Gets a template layer to create a signature appearance. The layers can go from 0 to 4,
 * but only layer 0 and 2 will be used if acro6Layers is true.
 * <p>
 * Consult <A HREF="http://partners.adobe.com/asn/developer/pdfs/tn/PPKAppearances.pdf">PPKAppearances.pdf</A>
 * for further details.
 * @param layer the layer
 * @return a template
 */
public PdfTemplate getLayer(int layer)