Java获取pdf文件签名信息

获取签名规则、签名时间、签名者、签名结果、证书、证书引证、签名算法标识

引入com.itextpdf

private static void pdfVerifyForXndx(FileAttribute fileAttribute) throws Exception {
        PdfReader pdfReader = new PdfReader(fileAttribute.getPath());
        AcroFields acroFields = pdfReader.getAcroFields();
        List<String> signatureNames = acroFields.getSignatureNames();
        if(org.apache.commons.collections.CollectionUtils.isNotEmpty(signatureNames)){
            String names = String.join(",", signatureNames);

            String signatureName = signatureNames.get(0);
            PdfDictionary signatureDictionary = acroFields.getSignatureDictionary(signatureName);

            //签名者姓名
            PdfString name = signatureDictionary.getAsString(PdfName.NAME);
            String nameStr = name != null ? name.toString() : null;
            fileAttribute.setSigner(nameStr);

            //签名日期
            PdfString asName = signatureDictionary.getAsString(PdfName.M);
            String MStr = asName != null ? asName.toString() : null;
            fileAttribute.setSignatureTime(MStr);

            //签名证书 -指定用于签署文档的证书。它包含证书序列号、有效期和颁发机构等信息。
            PdfString cert = signatureDictionary.getAsString(PdfName.CERT);
            String certStr = cert != null ? cert.toUnicodeString(): null ;
            fileAttribute.setCertificate(certStr);

            //签名规则
            PdfName filter = signatureDictionary.getAsName(PdfName.FILTER);
            //签名算法标识 SubFilter --指定用于解密签名数据的解密算法名称
            PdfName subFilter = signatureDictionary.getAsName(PdfName.SUBFILTER);
            String signatureRule ="";
            if (PdfName.ADOBE_PPKLITE.equals(filter) && PdfName.ADBE_PKCS7_DETACHED.equals(subFilter)) {
                signatureRule ="Detached signature with PKCS#7 format.";
            } else if (PdfName.ADOBE_PPKMS.equals(filter) && PdfName.ADBE_PKCS7_SHA1.equals(subFilter)) {
                signatureRule ="PKCS#7 signature with SHA-1 digest.";
            }else if(PdfName.XML.equals(filter) && PdfName.ADBE_X509_RSA_SHA1.equals(subFilter)){
                signatureRule ="XML Digital signature with adbe.x509.rsa_sha1.";
            } else {
                signatureRule =filter +" "+subFilter;
            }
            fileAttribute.setSignatureRule(signatureRule);

            //签名结果 BYTERANGE -通常用于验证签名的完整性
            String byterangeStr ="";
            PdfArray byterange = signatureDictionary.getAsArray(PdfName.BYTERANGE);
            if(byterange != null && byterange.size() > 0){
                for (int i = 0; i < byterange.size(); i++) {
                    PdfObject obj = byterange.getPdfObject(i); // 获取数组中的元素
                    byterangeStr += String.valueOf(obj) +" ";
                }
            }
            fileAttribute.setSignatureResult(byterangeStr);

            //证书引证
            PdfString asName1 = signatureDictionary.getAsString(PdfName.CONTACTINFO);
            PdfName asName2 = signatureDictionary.getAsName(PdfName.CRL);
            PdfName asName3 = signatureDictionary.getAsName(PdfName.OCSP);
            String asName1Str = asName1 != null ? asName1.toUnicodeString(): null ;
            String asName2Str = asName2 != null ? asName2.toString(): null ;
            String asName3Str = asName3 != null ? asName3.toString(): null ;
            fileAttribute.setCertificateRuote(asName1Str + " " +asName2Str+" "+asName3Str);
        }
    }