wget and open-uri

I have a question about open-uri in site of my kanshipin.net.
And my configuration info listed below:
os:Solar System
ruby:1.9.1p0
ror:2.3.2
when i tried to visit the url of
http://api.bd.joy.cn/rest?parameters…,
the wget can get correct result but the open-uri get http error of 404

The service api.bd.joy.cn used url-rewrite tech to handle request,but
why wget can
works well ,open-uri can not.

I need you help !

thanks!