feat: add java keystore certificate option for pdf signing

src/main/java/stirling/software/SPDF/controller/api/security/CertSignController.java

@@ -81,6 +81,7 @@ public class CertSignController {
         MultipartFile privateKeyFile = request.getPrivateKeyFile();
         MultipartFile certFile = request.getCertFile();
         MultipartFile p12File = request.getP12File();
+        MultipartFile jksfile = request.getJksFile();
         String password = request.getPassword();
         Boolean showSignature = request.isShowSignature();
         String reason = request.getReason();
@@ -95,10 +96,6 @@ public class CertSignController {
         KeyStore ks = null;
 
         switch (certType) {
-            case "PKCS12":
-                ks = KeyStore.getInstance("PKCS12");
-                ks.load(p12File.getInputStream(), password.toCharArray());
-                break;
             case "PEM":
                 ks = KeyStore.getInstance("JKS");
                 ks.load(null);
@@ -107,6 +104,14 @@ public class CertSignController {
                 ks.setKeyEntry(
                         "alias", privateKey, password.toCharArray(), new Certificate[] {cert});
                 break;
+            case "PKCS12":
+                ks = KeyStore.getInstance("PKCS12");
+                ks.load(p12File.getInputStream(), password.toCharArray());
+                break;
+            case "JKS":
+                ks = KeyStore.getInstance("JKS");
+                ks.load(jksfile.getInputStream(), password.toCharArray());
+                break;
             default:
                 throw new IllegalArgumentException("Invalid cert type: " + certType);
         }

src/main/java/stirling/software/SPDF/model/api/security/SignPDFWithCertRequest.java

@@ -14,7 +14,7 @@ public class SignPDFWithCertRequest extends PDFFile {
 
     @Schema(
             description = "The type of the digital certificate",
-            allowableValues = {"PKCS12", "PEM"})
+            allowableValues = {"PEM", "PKCS12", "JKS"})
     private String certType;
 
     @Schema(
@@ -28,6 +28,9 @@ public class SignPDFWithCertRequest extends PDFFile {
     @Schema(description = "The PKCS12 keystore file (required for PKCS12 type certificates)")
     private MultipartFile p12File;
 
+    @Schema(description = "The JKS keystore file (Java Key Store)")
+    private MultipartFile jksFile;
+
     @Schema(description = "The password for the keystore or the private key")
     private String password;