How to export private key from a keystore of self-signed certificate

Question

I just created a self-signed certificate on a linux box running tomcat 6.

I created the keys like this, valid for 10 years:

keytool -genkey -alias to         


        

Answer 1

http://anandsekar.github.io/exporting-the-private-key-from-a-jks-keystore/

public class ExportPrivateKey {
        private File keystoreFile;
        private String keyStoreType;
        private char[] password;
        private String alias;
        private File exportedFile;

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

        public void export() throws Exception{
                KeyStore keystore=KeyStore.getInstance(keyStoreType);
                BASE64Encoder encoder=new BASE64Encoder();
                keystore.load(new FileInputStream(keystoreFile),password);
                KeyPair keyPair=getPrivateKey(keystore,alias,password);
                PrivateKey privateKey=keyPair.getPrivate();
                String encoded=encoder.encode(privateKey.getEncoded());
                FileWriter fw=new FileWriter(exportedFile);
                fw.write(“—–BEGIN PRIVATE KEY—–\n“);
                fw.write(encoded);
                fw.write(“\n“);
                fw.write(“—–END PRIVATE KEY—–”);
                fw.close();
        }


        public static void main(String args[]) throws Exception{
                ExportPrivateKey export=new ExportPrivateKey();
                export.keystoreFile=new File(args[0]);
                export.keyStoreType=args[1];
                export.password=args[2].toCharArray();
                export.alias=args[3];
                export.exportedFile=new File(args[4]);
                export.export();
        }
}