如何使用BouncyCastle在Java中通过PEMParser读取不带BEGIN和END的PEM证书

我有一个 cert.PEM 我以这种方式创建的文件:

Base64 encoder = new Base64();
File file = new File(certPath + "cert.pem");
file.createNewFile();
writer = new FileWriter(file);
writer.write(new String(encoder.encode(cert.getEncoded())));
writer.close();

它没有 ----BEGIN CERTIFICATE---- 和 -----END CERTIFICATE----- 部分。它的原始形式如下:

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

现在我想再次读取它并将其解析为 X509CertificateHolder 按此代码:

PEMParser r = new PEMParser(new FileReader(certFile));
            System.out.println(r.ready());
            PemObject object = r.readPemObject();
            X509CertificateHolder cert = new X509CertificateHolder(object.getContent());
            Date date = new Date();
            if (date.compareTo(cert.getNotAfter()) > 0)
            {
                generateCert();
            }

我明白了:

java.lang.NullPointerException
    at com.sunova.bot.Launcher.<init>(Launcher.java:67)
    at com.sunova.bot.Launcher.getInstance(Launcher.java:41)
    at com.sunova.bot.Launcher.main(Launcher.java:48)

这是由于 r.readPemObject() 返回null。我该怎么办?