先看我遇到的问题：试图使用如下rewrite代码
RewriteEngine On
RewriteBase /dex/
RewriteRule ^wsdl/(sjz|bd|qhd|common)/?$ wsdl.php?u=$1 [L]
RewriteRule ^wsdl/?$ wsdl.php [L]
达到以下转换效果：
wsdl/sjz –> wsdl.php?u=sjz
wsdl/ –> wsdl.php
但天不随人愿，第二行转换效果没问题，第一行转换效果总是出不来，查了一下RewriteLog，有一句引起了我的注意：
(1) pass through /dex/wsdl/sjz
(3) [per-dir E:/cvswork/2005dex/] add path info postfix: E:/cvswork/2005dex/wsdl.php -> E:/cvswork/2005dex/wsdl.php/sjz
注意看第二句，它怎么把wsdl/sjz转换成了wsdl.php/sjz？难道和第二句RewriteRule有关？试着把第二句RewriteRule关掉，问题依旧。
于是祭起Google海搜，发现有人和我遇到了同样的问题：
the problem lies in here somewhere
with URL http://localhost/index/q we get:-
add path-info postfix: c:/wwwroot/index.php -> c:/wwwroot/index.php/q
strip per-dir prefix: c:/wwwroot/index.php/q -> index.php/q
applying pattern ‘^([^/.]*)$’ to uri ‘index.php/q’
I dont want index.php/q though!!!!! argghhhhh!!!
……
GOT IT!!!!!!!
Bl**dy windows OS
i removed the .htaccess file and http://localhost/phpinfo/x was still doing phpinfo.php
I added a directory called phpinfo and it worked – giving a directory listing
I re-created the .htaccess and voila it worked.
So basically if a directory doesnt exist it looks for a script (.php .html) and then uses that with further parameters sdded to the end of it.
I have to find a workaround for that now.
原来，是Apache在当前目录下找到了wsdl.php（依据wsdl/sjz中的wsdl），并且来了个狸猫换太子，继续搜索……终于在这个德语网页找到了答案：
MultiViews-option abschalten.
wenn diese aktiviert ist, würde ein request nach /kategorie auch kategorie.php finden, und das kollidiert natürlich mit deiner RewriteRule, weil dort eben mit /kategorie/irgendwas ebenfalls ein “treffer” vorliegt – da kann der server also nicht entscheiden, was jetzt eigentlich gemeint ist.
上面是德语，我是看不懂的，用Google翻译如下：
MultiViews option switch off.
if this is activated, after/category kategorie.php to also find request, and collides naturally with your RewriteRule, because evenly with/category/something is likewise present there a “hit” – there the server cannot decide thus, what is now actually meant.
原来是Apache的MultiViews选项干扰了RewriteRule，将其去掉之后，问题排除。
Options -MultiViews
继续寻找MultiViews的相关信息，收获如下：
所以，在没有明确需要的情况下，一般不要打开MultiViews选项，因为我们一般编写的程序很少用到它，反而会给正常的程序调试带来麻烦，另外早期的版本可能还存在一些安全问题。
在去掉MultiViews的同时，发现还有一个好像也没有用的Options——FollowSymLinks，但如果你的RewriteRule是写在.htaccess文件中的话，FollowSymLinks这个选项可不能去掉，去掉了RewriteEngine就不干活啦～～
Note
To enable the rewriting engine for per-directory configuration files you need to set “RewriteEngine On” in these files and “Options FollowSymLinks” must be enabled. If your administrator has disabled override of FollowSymLinks for a user’s directory, then you cannot use the rewriting engine. This restriction is needed for security reasons.