How do I list / export private keys from a keystore?

Question

How do I list and export a private key from a keystore?

Answer 1

Here is a shorter version of the above code, in Groovy. Also has built-in base64 encoding:

import java.security.Key
import java.security.KeyStore

if (args.length < 3)
        throw new IllegalArgumentException('Expected args:     ')

def keystoreName = args[0]
def keystoreFormat = args[1]
def keystorePassword = args[2]
def alias = args[3]
def keyPassword = args[4]

def keystore = KeyStore.getInstance(keystoreFormat)
keystore.load(new FileInputStream(keystoreName), keystorePassword.toCharArray())
def key = keystore.getKey(alias, keyPassword.toCharArray())

println "-----BEGIN PRIVATE KEY-----"
println key.getEncoded().encodeBase64()
println "-----END PRIVATE KEY-----"