How to export a private key from a java key store

This sample code shows how to export a private key from a Java Key store.

// Sample code taken from http://forum.java.sun.com/thread.jspa?threadID=154587&messageID=1403909
// How to export the private key from keystore?
// Does keytool not have an option to do so?
// This example use the "testkeys" file that comes with JSSE 1.0.3

*import* sun.misc.BASE64Encoder;
*import* java.security.cert.Certificate;
*import* java.security.*;
*import* java.io.File;
*import* java.io.FileInputStream;

*class* ExportPriv {
   *public* *static* *void* main(String args[]) *throws* Exception{
        ExportPriv myep = *new* ExportPriv();
        myep.doit();
   }

   *public* *void* doit() *throws* Exception{

        KeyStore ks = KeyStore.getInstance("JKS");
        String fileName = "testkeys";

        *char*[] passPhrase = "passphrase".toCharArray();
        BASE64Encoder myB64 = *new* BASE64Encoder();
        File certificateFile = *new* File(fileName);
        ks.load(*new* FileInputStream(certificateFile), passPhrase);
        KeyPair kp = getPrivateKey(ks, "duke", passPhrase);
        PrivateKey privKey = kp.getPrivate();
    
        String b64 = myB64.encode(privKey.getEncoded());

        System.out.println("-----BEGIN PRIVATE KEY-----");
        System.out.println(b64);
        System.out.println("-----END PRIVATE KEY-----");
    }

// From http://javaalmanac.com/egs/java.security/GetKeyFromKs.html

  *public* KeyPair getPrivateKey(KeyStore keystore, String alias, *char*[] password) {
       *try* {
           // Get private key
           Key key = keystore.getKey(alias, password);
           *if* (key *instanceof* PrivateKey) {
               // Get certificate of public key
               Certificate cert = keystore.getCertificate(alias);
                  // Get public key
               PublicKey publicKey = cert.getPublicKey();
                  // Return a key pair
               *return* *new* KeyPair(publicKey, (PrivateKey)key);
           }
       } *catch* (UnrecoverableKeyException e) {
       } *catch* (NoSuchAlgorithmException e) {
       } *catch* (KeyStoreException e) {
       }
       *return* *null*;
   }
}