With a spire. Doctor. For Java, you can add and verify digital signatures. Please refer to the code:

Import? com . spire . pdf . *；

Import? com . spire . pdf . graphics . pdf image；

Import? com . spire . pdf . graphics . pdftruetypefont；

Import? com . spire . pdf . security . graphic mode；

Import? com . spire . pdf . security . pdf certificate；

Import? com . spire . pdf . security . pdf certification flags；

Import? com . spire . pdf . security . pdf signature；

Import? Java . awt . *；

Import? Java . awt . geom . point 2d；

Import? Java . awt . geom . rectangle 2d；

Public? Class? Add certificate? {

Public? Static electricity Invalid? main(String[]args){

//load PDF document

PdfDocument？ Doctor. =? New? pdf document()；

doc . loadfromfile(" test . pdf ")；

//Load the pfx certificate and certificate key.

PdfCertificate？ Certificate? =? New? PdfCertificate("Cermia.pfx "，" 123654yes！" );

//Add a digital signature to the specified page and set its location and size.

PdfSignature？ Signature? =? New? PdfSignature(doc，doc.getPages()。 get(2)，？ Certificate? "My signature");

Rectangle2D？ rect？ =? New? Rectangular 2D. float()；

Rect.setFrame (new? Point 2D Floating ((floating)? doc.getPages()。 Get (0). getActualSize()。 getWidth()？ -? 340,? (floating)? doc.getPages()。 Get (0). getActualSize()。 getHeight()？ -? 230),? New? Dimension (280,? 150));

signature . set bounds(rect)；

//Set the signature to picture plus text mode.

signature . setgraphicmode(GraphicMode。 Logo _ image _ and _ logo _ details);

//Set the content of the signature

signature . setname label(" signer:")；

signature . setname(" Mia ")；

signature . setcontactinfolabel(" Tel:")；

signature . setcontactinfo(" 0288 1705 109 ")；

signature . set date label(" date:")；

Signature.setDate (new? Java . util . date())；

signature . setlocationinfolabel(" location:")；

Signature.setLocationInfo ("Chengdu");

signature . setreasonlabel(" reason:")；

Signature.setReason ("document owner");

signature . setdistinguishednamelabel(" DN:");

signature . setdistinguishedname(signature . get certificate()。 get_IssuerName()。 getName())；

signature . setsignimagesource(pdf image . from file(" sign . png "))；

//Set the font of the signature

Signature.setSignDetailsFont (new? PdfTrueTypeFont (new? Font ("Arial? Unicode？ ",,lady? Font. Flat and faint? 9)));

//Set document permissions to prevent changes.

signature . setdocumentpermissions(PdfCertificationFlags。 Prohibit _ change);

signature . set certified(true)；

//Save the document

doc . savetofile(" add signature . pdf ")；

doc . close()；

}

} Digital signature adding effect:

Digital signature effect

Refer to the original text