Can't recognize the Pkcs12

Question

I programmed to accomplish the downloading of a pkcs12 certificate, but after it had saved in the local disk, I can't open it.
It show the error: "This is a invalid Personnel Information Exchange File".
my main servlet code is following:
InputStreamReader in = null;
StringBuffer buf = new StringBuffer();
OutputStreamWriter out = null;
response.setContentType("p12");
try{
out = new OutputStreamWriter(response.getOutputStream());
// CertFilePath is the saving path of Pkcs12 file at the server
File fp = new File(certFilePath);
in = new InputStreamReader(new FileInputStream(certFilePath));
long fsize = fp.length() ;
char[] filechars = new char[(int)fsize];
in.read(filechars);
buf.append(filechars);
in.close();
String str_certInfo = buf.toString();
out.write(str_certInfo);
out.close();
I don't know if the method is unreasonable.
please give me some help, thanks.

Answer 1

I want to know
if the reason is that the SUN jsse don't support the writing of PKCS12.
In order to realize the transmission ,must I getting the third provider?
such as BouncyCastle.