本文介绍如何使用Spire.PDF for Java为PDF文档添加数字签名时添加一个可信时间戳。

import com.spire.pdf.PdfDocument;
import com.spire.pdf.graphics.*;
import com.spire.pdf.security.GraphicMode;
import com.spire.pdf.security.PdfCertificate;
import com.spire.pdf.security.PdfCertificationFlags;
import com.spire.pdf.security.PdfSignature;

import java.awt.*;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;

public class SignWithTimestamp {
    public static void main(String[] args) {

        //加载PDF文档
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("C:\\Users\\Administrator\\Desktop\\Introduction.pdf");

        //加载pfx文档
        PdfCertificate cert = new PdfCertificate("C:\\Users\\Administrator\\Desktop\\gary.pfx", "e-iceblue");

        //添加数字签名，设置其位置和大小
        PdfSignature signature = new PdfSignature(doc, doc.getPages().get(0), cert, "MySignature");
        Rectangle2D rect = new Rectangle2D.Float();
        rect.setFrame(new Point2D.Float((float) doc.getPages().get(0).getActualSize().getWidth() - 220, (float) doc.getPages().get(0).getActualSize().getHeight() - 140), new Dimension(200, 100));
        signature.setBounds(rect);

        //设置签名为文本模式
        signature.setGraphicMode(GraphicMode.Sign_Detail);

        //设置签名的内容
        signature.setNameLabel("签字者：");
        signature.setName("Gary");
        signature.setContactInfoLabel("联系电话：");
        signature.setContactInfo("02881705109");
        signature.setLocationInfoLabel("地点：");
        signature.setLocationInfo("成都");
        signature.setReasonLabel("原因：");
        signature.setReason("我是文档所有者");

        //设置签名的字体
        signature.setSignDetailsFont(new PdfTrueTypeFont(new Font("宋体", Font.PLAIN, 12)));

        //设置文档权限为禁止更改
        signature.setDocumentPermissions(PdfCertificationFlags.Forbid_Changes);
        signature.setCertificated(true);

        //配置时间戳服务器
        String timestampeServerUrl = "http://timestamp.digicert.com";
        signature.configureTimestamp(timestampeServerUrl);

        //保存文档
        doc.saveToFile("output/Timestamp.pdf");
        doc.close();
    }
}