Java - 如何将X509Certificate链数据导出到Base64编码的证书文件？

Question

When I receive X509Certificate chain on SSL Handshake in my socket connection, I have to export X509Certificate chain to a base64 encoded .cer file.

I tried with below code. But the file content is not as same with original certificate.

private static final String BEGIN_CERT = "-----BEGIN CERTIFICATE-----";

private static final String END_CERT = "-----END CERTIFICATE-----";

X509Certificate[] x509Certificates;


   --------------
   --------------


  String certContent="";

  for(int i=0;i<x509Certificates.length;i++)   
  {  

         certContent += Base64.encode(x509Certificates[i].getEncoded());

  } 



BufferedWriter writer = new BufferedWriter(new FileWriter("mycert.cer"));

writer.write(BEGIN_CERT);

writer.newLine();

writer.write(certContent);

writer.newLine();

writer.write(END_CERT);

writer.close();

Any suggestion/correction in above code?

Answer 1

I believe your code is concatenating the certificates together and then adding the BEGIN and END tags around the whole thing.

Instead try placing the BEGIN/END tags around EACH certificate within the same file.

For example

-----BEGIN CERTIFICATE-----
<Base64 cert1 data>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<Base64 cert2 data>
-----END CERTIFICATE-----

-----BEGIN CERTIFICATE-----
<Base64 certN data>
-----END CERTIFICATE-----