e225. importing a certificate from a file.txt

这里面包含了一百多个JAVA源文件

See also e224 Exporting a Certificate to a File. 
    // This method reads a certificate to a file. The certificate can be either
    // binary or base64 encoded.
    public static java.security.cert.Certificate importCertificate(File file) {
        try {
            FileInputStream is = new FileInputStream(file);
    
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            java.security.cert.Certificate cert = cf.generateCertificate(is);
            return cert;
        } catch (CertificateException e) {
        } catch (IOException e) {
        }
        return null;
    }

A certificate can be imported into a keystore using keytool: 
    > keytool -storepass my-keystore-password -alias myalias -import -file infilename.cer