1. A data processing method in a computer comprising responding to a certain processing request with cached data, comprising the steps of: caching data for responding to a first processing request in memory by using a data file included in the first processing request as a key; and for a second processing request made after caching the data, searching for the data cached in the memory by using a data file included in the second processing request as a key, and if the cached data corresponds to the second processing request, responding to the second processing request with the cached data.