Apache 安装后，默认的 DocumentRoot 是安装目录下的 htdocs 目录，编程时有很多不便，如需更改，打开安装目录 conf 子目录下的 httpd.conf 文件，修改 DocumentRoot 属性即可，如更改为：DocumentRoot “E:/My/DocRoot”。
在 IIS 下，新建虚拟目录可通过可视化界面操作，在 Apache 中，新建虚拟目录通过修改 httpd.conf 文件实现。
在 httpd.conf 的 alias_module 下增加一别名定义项，如：Alias “/onefly” “E:/My/Onefly” ，即可定义虚拟目录。
更改以上设置后，必须重启 Apache 才能使设置生效。同时，要对相应目录作权限定义，否则会出现无权访问的错误提示。
要对目录定义权限，可在 httpd.conf 文件中定义类似以下的代码：
<Directory “E:/My/Onefly”>
Options Indexes FollowSymLinks
AllowOverride None
Order allow,deny
Allow from all
</Directory>
=======================================================================
自己机器上配置实例如下：
<IfModule alias_module>
#
# Redirect: Allows you to tell clients about documents that used to
# exist in your server's namespace, but do not anymore. The client
# will make a new request for the document at its new location.
# Example:
# Redirect permanent /foo http://www.waydu.com/bar
#
# Alias: Maps web paths into filesystem paths and is used to
# access content that does not live under the DocumentRoot.
# Example:
# Alias /webpath /full/filesystem/path
##################################################################
Alias /study "D:/PHP/www/study"
<Directory "D:/PHP/www/study">
Options Indexes Includes FollowSymLinks MultiViews IncludesNoExec
AllowOverride None
Order allow,deny
Allow from all
</Directory>
##################################################################
#
# Redirect: Allows you to tell clients about documents that used to
# exist in your server's namespace, but do not anymore. The client
# will make a new request for the document at its new location.
# Example:
# Redirect permanent /foo http://www.waydu.com/bar
#
# Alias: Maps web paths into filesystem paths and is used to
# access content that does not live under the DocumentRoot.
# Example:
# Alias /webpath /full/filesystem/path
##################################################################
Alias /study "D:/PHP/www/study"
<Directory "D:/PHP/www/study">
Options Indexes Includes FollowSymLinks MultiViews IncludesNoExec
AllowOverride None
Order allow,deny
Allow from all
</Directory>
##################################################################
