正如你说你已经**“mod_rewrite已经启用”**
尝试编辑/etc/apache2/sites-enabled/000-default或/etc/apache2/apache2.conf

<Directory /var/www/>
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    allow from all
</Directory>

将AllowOverride None更改为AllowOverride All

/etc/apache2/mods-available/alias.conf中的注解别名。

<IfModule alias_module>
    # Aliases: Add here as many aliases as you need (with no limit). The format is
    # Alias fakename realname
    #
    # Note that if you include a trailing / on fakename then the server will
    # require it to be present in the URL.  So "/icons" isn't aliased in this
    # example, only "/icons/".  If the fakename is slash-terminated, then the
    # realname must also be slash terminated, and if the fakename omits the
    # trailing slash, the realname must also omit it.
    #
    # We include the /icons/ alias for FancyIndexed directory listings.  If
    # you do not use FancyIndexing, you may comment this out.

#   Alias /icons/ "/usr/share/apache2/icons/"

#   <Directory "/usr/share/apache2/icons">
#       Options FollowSymlinks
#       AllowOverride None
#       Require all granted
#   </Directory>

</IfModule>

在注解这些行之后，使用以下命令检查apache conf：

sudo apache2ctl -t

然后重新加载apache2：

sudo systemctl reload apache2