最近在研究Itext对pdf进行签章，记录一下。
可参照：http://developers.itextpdf.com/examples/security-itext5/digital-signatures-white-paper中的例子
一。准备相关文件：
1.背景色为空的印章图片
2.扩展名为.p12的证书（可自行百度keytool 生成证书 pkcs12）
3.一个使用acrobat处理过的pdf模板（使用数字签名表单）
二。引入相关maven依赖：
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itextpdf</artifactId>
<version>5.5.11</version>
</dependency>
<dependency>
<groupId>com.itextpdf</groupId>
<artifactId>itext-asian</artifactId>
<version>5.2.0</version>
</dependency>
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>1.49</version>
</dependency>
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcpkix-jdk15on</artifactId>
<version>1.49</version>
</dependency> 三。编写相关代码，
1.编写签章类，收集签章相关信息
package com.example.itext.utils; import com.itextpdf.text.pdf.PdfSignatureAppearance; import com.itextpdf.text.pdf.security.MakeSignature; import lombok.Data; import java.security.PrivateKey; import java.security.cert.Certificate; @Data public class SignatureInfo { private String reason; //理由 private String location;//位置 private String digestAlgorithm;//摘要类型 private String imagePath;//图章路径 private String fieldName;//表单域名称 private Certificate[] chain;//证书链 private PrivateKey pk;//私钥 private int certificationLevel = 0; //批准签章 private PdfSignatureAppearance.RenderingMode renderingMode;//表现形式：仅描述，仅图片，图片和描述，签章者和描述 private MakeSignature.CryptoStandard subfilter;//支持标准，CMS,CADES }2.编写工具类，红色字体为完成签章的主体逻辑，以ByteArrayOutputStream充当输出流是为了完成多次签章，期间不会生成临时文件。MakeSignature.signDetached()方法每调用一次，必须重新获取
PdfSignatureAppearance对象，因为分析源码方法可知，该方法调用时，appearance对象的preClosed参数会被置为false。package com.example.itext.utils; import com.itextpdf.text.DocumentException; import com.itextpdf.text.Image; import com.itextpdf.text.pdf.PdfReader; import com.itextpdf.text.pdf.PdfSignatureAppearance; import com.itextpdf.text.pdf.PdfStamper; import com.itextpdf.text.pdf.security.BouncyCastleDigest; import com.itextpdf.text.pdf.security.DigestAlgorithms; import com.itextpdf.text.pdf.security.ExternalDigest; import com.itextpdf.text.pdf.security.ExternalSignature; import com.itextpdf.text.pdf.security.MakeSignature; import com.itextpdf.text.pdf.security.PrivateKeySignature; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.security.GeneralSecurityException; import java.security.KeyStore; import java.security.PrivateKey; import java.security.cert.Certificate;
public class ItextUtil { public static final char[] PASSWORD = "123456".toCharArray();//keystory密码
/** * 单多次签章通用 * @param src * @param target * @param signatureInfos * @throws GeneralSecurityException * @throws IOException * @throws DocumentException */
public void sign(String src, String target, SignatureInfo... signatureInfos){ InputStream inputStream = null; FileOutputStream outputStream = null; ByteArrayOutputStream result = new ByteArrayOutputStream(); try { inputStream = new FileInputStream(src); for (SignatureInfo signatureInfo : signatureInfos) { ByteArrayOutputStream tempArrayOutputStream = new ByteArrayOutputStream(); PdfReader reader = new PdfReader(inputStream); //创建签章工具PdfStamper ，最后一个boolean参数是否允许被追加签名 PdfStamper stamper = PdfStamper.createSignature(reader, tempArrayOutputStream, '\0', null, true); // 获取数字签章属性对象 PdfSignatureAppearance appearance = stamper.getSignatureAppearance(); appearance.setReason(signatureInfo.getReason()); appearance.setLocation(signatureInfo.getLocation()); //设置签名的签名域名称，多次追加签名的时候，签名预名称不能一样，图片大小受表单域大小影响（过小导致压缩） appearance.setVisibleSignature(signatureInfo.getFieldName()); //读取图章图片 Image image = Image.getInstance(signatureInfo.getImagePath()); appearance.setSignatureGraphic(image); appearance.setCertificationLevel(signatureInfo.getCertificationLevel()); //设置图章的显示方式，如下选择的是只显示图章（还有其他的模式，可以图章和签名描述一同显示） appearance.setRenderingMode(signatureInfo.getRenderingMode()); // 摘要算法 ExternalDigest digest = new BouncyCastleDigest(); // 签名算法 ExternalSignature signature = new PrivateKeySignature(signatureInfo.getPk(), signatureInfo.getDigestAlgorithm(), null); // 调用itext签名方法完成pdf签章 MakeSignature.signDetached(appearance, digest, signature, signatureInfo.getChain(), null, null, null, 0, signatureInfo.getSubfilter()); //定义输入流为生成的输出流内容，以完成多次签章的过程
inputStream = new ByteArrayInputStream(tempArrayOutputStream.toByteArray()); result = tempArrayOutputStream; } outputStream = new FileOutputStream(new File(target)); outputStream.write(result.toByteArray()); outputStream.flush(); } catch (Exception e) { e.printStackTrace(); } finally { try { if(null!=outputStream){ outputStream.close(); } if(null!=inputStream){ inputStream.close(); } if(null!=result){ result.close(); } } catch (IOException e) { e.printStackTrace(); } } } public static void main(String[] args) { try { ItextUtil app = new ItextUtil(); //将证书文件放入指定路径，并读取keystore ，获得私钥和证书链
String pkPath = app.getClass().getResource("/template/zhengshu.p12").getPath(); KeyStore ks = KeyStore.getInstance("PKCS12"); ks.load(new FileInputStream(pkPath), PASSWORD); String alias = ks.aliases().nextElement(); PrivateKey pk = (PrivateKey) ks.getKey(alias, PASSWORD); Certificate[] chain = ks.getCertificateChain(alias); String src = app.getClass().getResource("/template/check.pdf").getPath();
//封装签章信息 SignatureInfo info = new SignatureInfo(); info.setReason("理由"); info.setLocation("位置"); info.setPk(pk); info.setChain(chain); info.setCertificationLevel(PdfSignatureAppearance.NOT_CERTIFIED); info.setDigestAlgorithm(DigestAlgorithms.SHA1); info.setFieldName("sig1"); info.setImagePath(app.getClass().getResource("/template/yinzhang.png").getPath()); info.setRenderingMode(PdfSignatureAppearance.RenderingMode.GRAPHIC); SignatureInfo info1 = new SignatureInfo(); info1.setReason("理由1"); info1.setLocation("位置1"); info1.setPk(pk); info1.setChain(chain); info1.setCertificationLevel(PdfSignatureAppearance.NOT_CERTIFIED); info1.setDigestAlgorithm(DigestAlgorithms.SHA1); info1.setFieldName("sig2"); info1.setImagePath(app.getClass().getResource("/template/yinzhang.png").getPath()); info1.setRenderingMode(PdfSignatureAppearance.RenderingMode.GRAPHIC); app.sign(src, "D://sign.pdf", info,info1);
} catch (Exception e) { // TODO Auto-generated catch block
e.printStackTrace(); } } }至此，电子签章的代码整理完毕。
转载于:https://www.cnblogs.com/watershine/p/6928669.html
