keytool -v -importkeystore -srckeystore .keystore -srcalias mykey -destkeystore myp12file.p12 -deststoretype PKCS12

Enter destination keystore password: 
Re-enter new password: 
Enter source keystore password: 
[Storing myp12file.p12]

openssl pkcs12 -in myp12file.p12 -nocerts -nodes

Enter Import Password:
MAC verified OK
Bag Attributes
 friendlyName: mykey
 localKeyID: 54 69 6D 65 20 31 32 37 31 32 37 38 35 37 36 32 35 37 
Key Attributes: 
-----BEGIN RSA PRIVATE KEY-----
MIIC...
.
.
.
-----END RSA PRIVATE KEY-----