有关 apache Proxy 的特别参数，供大家参考。
1.SetEnv force-proxy-request-1.0 1
2.SetEnv proxy-nokeepalive 1
不加这两个选项，可能会导致ie5.5等浏览器访问异常，时好时坏。出现以下提示：
Http 502 Proxy Error
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /.
Reason: Error reading from remote server
引用
For circumstances where mod_proxy is sending requests to an origin server that
doesn't properly implement keepalives or HTTP/1.1, there are two environment
variables that can force the request to use HTTP/1.0 with no keepalive. These are set via the SetEnv directive.
These are the force-proxy -request-1.0 and proxy -nokeepalive notes.
大概是这意思(不是我译的):
当mod_proxy向一个没有正确实现持久连接(KeepAlive)或HTTP/1.1的原始服务器发送请求的时候，可以通过设置两个环境变量来发送不带持久连接(KeepAlive)的HTTP/1.0请求。这两个变量是通过SetEnv指令设置的。
force-proxy-request-1.0和proxy -nokeepalive的例子：
重启apache后生效。
参考文章：
http://httpd.apache.org/docs/2.3/mod/mod_proxy.html
ProxyPass、 ProxyPassReverse
这两个配置时，如果不加 ProxyPassReverse 这行，则IE地址栏里面显示就是Apache代理后端应用服务器（比如tomcat）所对就的地址，反之，加上ProxyPassReverse这行，则显示的就是Apache的地址，把原tomcat给隐藏了。