DirectoryIndex doesn't work

I use apache2 to host a site. There are both index.html and index.php in my directory.

I open the /etc/apache2/apache2.conf and add a line:

DirectoryIndex index.php index.html index.htm

Then restart apache2. But when I open localhost/~username, it a开发者_C百科ccesses the index.html.

I look around but can't find problem. My httpd.conf is empty and I don't have .htaccess file.

Where may the setting hide?

Edit: After I modified /etc/apache2/mods-availiable/dir.conf, it finds the index.php.

But WHY the apache2.conf can't overwrite dir.conf?!

I think mod_dir isn't loaded, try to command sudo a2enmod dir and service apache2 restart

Create a file named .htaccess in the directory where you want this behavior to occur. Inside the .htaccess file, put a single line beginning with DirectoryIndex followed by the list of filenames that you want Apache to serve first when a directory has been requested, like so:

DirectoryIndex index.php index.html index.htm index.phtml start.html

The above directive must be all on a single line in the .htaccess file.