解决方案:
We redirect the URL / to /about/:
RewriteEngine on
RewriteRule ^/$ /about/ [R]
Note that this can also be handled using the RedirectMatch directive:
RedirectMatch ^/$ http://example.com/about/
Note also that the example rewrites only the root URL. That is, it rewrites a request for http://example.com/, but not a request for http://example.com/page.html. If you have in fact changed your document root - that is, if all of your content is in fact in that subdirectory, it is greatly preferable to simply change your DocumentRoot directive, or move all of the content up one directory, rather than rewriting URLs.
这是取自http://httpd.apache.org/docs/trunk/rewrite/remapping.html#page-header的解决方案,请参阅移动的 DocumentRoot 标题。