验签: testarea-itext5/src/test/java/mkl/testarea/itext5/signature/VerifySignature.java
签署: testarea-itext5/src/test/java/mkl/testarea/itext5/signature/CreateSignature.java
获取证书信息: testarea-itext5/src/main/java/mkl/testarea/itext5/signature/SignatureExtractor.java