正确配置将所有http子域重定向到https

Question

我有一个apache的以下配置。

<VirtualHost *:80>
    ServerName example.com
    Redirect permanent / https://example.com/
</VirtualHost>
<VirtualHost *:443>
    ServerName example.com
    SSLEngine on
    SSLCertificateFile <path to ssl certificate file>
    SSLCertificateKeyFile <path to key file>
    SSLCACertificateFile <path to CA certificate file>
</VirtualHost>

我需要帮助才能将所有http子域重定向到https子域。提前谢谢。

e.g。

1. http://example.com至https://www.example.com
2. https://example.com至https://www.example.com
3. http://subdomain.example.com至https://subdomain.example.com