分配和验证数字签名
数字签名可以确保工作簿文件有效,并且没有人对其进行了更改。您可以使用Microsoft Office套件附带的SELFCERT工具或其他工具创建个人数字签名。您甚至可以购买数字签名。创建或获取数字签名后,您必须将其附加到工作簿上。附加数字签名类似于封装一个信封。如果一个信封封装良好,您就可以一定程度上确信没有人篡改其内容。
Aspose.Cells for Java API 提供 com.aspose.cells.DigitalSignatureCollection 和 com.aspose.cells.DigitalSignature 类来签署电子表格以及验证它们。
签署电子表格
签署过程需要如上所述的证书。与证书一起,人们还应该知道其密码,以便使用Aspose.Cells API成功签署电子表格。
以下代码片段展示了使用 Aspose.Cells for Java API 签名电子表格的用法。
// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-Java | |
// The path to the documents directory. | |
String dataDir = Utils.getDataDir(SigningSpreadsheets.class); | |
// Create an instance of DigitalSignatureCollection | |
DigitalSignatureCollection signatures = new DigitalSignatureCollection(); | |
// Load the certificate into an instance of InputStream | |
InputStream inStream = new FileInputStream("d:/temp.pfx"); | |
// Create an instance of KeyStore with PKCS12 cryptography | |
KeyStore inputKeyStore = KeyStore.getInstance("PKCS12"); | |
// Use the KeyStore.load method to load the certificate stream and its password | |
inputKeyStore.load(inStream, KEYSTORE_PASSWORD.toCharArray()); | |
// Create an instance of DigitalSignature and pass the instance of KeyStore, password, comments and time | |
DigitalSignature signature = new DigitalSignature(inputKeyStore, KEYSTORE_PASSWORD, "test for sign", | |
DateTime.getNow()); | |
// Add the instance of DigitalSignature into the collection | |
signatures.add(signature); | |
// Load an existing spreadsheet using the Workbook class | |
Workbook workbook = new Workbook(dataDir + "unsigned.xlsx"); | |
// Set the signature | |
workbook.setDigitalSignature(signatures); | |
// Save the signed spreadsheet | |
workbook.save(dataDir + "signed.xlsx"); |
验证电子表格
以下代码片段演示了使用Aspose.Cells for Java API验证电子表格的用法。
// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-Java | |
// The path to the documents directory. | |
String dataDir = Utils.getDataDir(ValidatingSpreadsheets.class); | |
// Load an existing spreadsheet in an instance of Workbook | |
Workbook workbook = new Workbook(dataDir + "signed.xlsx"); | |
// Retrieve the collection of digital signatures from the Workbook | |
DigitalSignatureCollection signatures = workbook.getDigitalSignature(); | |
// Loop over the collection of digital signatures | |
for (DigitalSignature signature : (Iterable<DigitalSignature>) signatures) { | |
// Check the signature status using the isValid property | |
System.out.println(signature.isValid()); | |
} |