apiname=com.alipay.account.auth&app_id=2014100900013222&app_name=mc&auth_type=authaccount&biz_type=openservice&method=alipay.open.auth.sdk.code.get&pid=2088501624560335&product_id=app_fast_login&scope=kuaijie&target_id=1563867159976&sign_type=rsa2
string sign=alipaysignature.rsasign("content", private_key(商户私钥), charset, sign_type);
