Due to security reason at any instance if you want to disable http on your apache2 webserver comment following lines in /etc/apache2/ports.conf file.
First open /etc/apache2/ports.conf file with any editor.
Then search for following line in ports.conf file.
NameVirtualHost *:80 Listen 80
Comment above mentioned lines:
#NameVirtualHost *:80 #Listen 80
After commenting restart apache2.
$ service apache2 restart
Now try to access your website with http, it should show message as unable to connect.