Redirect all posts permalinks from ".html" to "/"

Question

How can I redirect all posts permalinks from .html to / in WordPress?

To be more clear, for example, a post URL like this:

http://example.com/%category%/%postname%.html

To be redirected to:

http://example.com/news/%postname%/.html

It's simple to redirect them one by one, but I need a rule to redirect all posts. My current .htaccess setup is:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Answer 1

Add this to your .htaccess below the # END WordPress line:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST}
RewriteRule ^(.*)/(.*).html$ news/$2/.html [L,R=301]
</IfModule>

This will redirect domains such as:

http://example.com/category/post-name.html

To the following:

http://example.com/news/post-name/.html