use dict share data between url mapping classes

[wencheng]

 I use web.py to build my restful web services. I have two urls mapping to two different classes, and all these are written in on python script file. I use a global dict as cache, I put some thing in the dict cache in the first calss's GET method, and I want to get the data in second class  I just put. but I got the dict empty. I don't konw why. Can some one help me? Thanks