1. A computer-implemented search ranking method suitable for a file system, comprising: receiving a query via a computer; calculating final relevance scores of individual file items via said computer with respect to said query at least partially in accordance with energy scores of individual nodes on a current file system energy tree, and outputting a list of search results based on said final relevance scores; and updating said energy scores of said individual nodes on said file system energy tree via said computer in response to an operation on said file system performed by a user, wherein said file system energy tree has a tree structure corresponding to that of said file system, and said individual nodes thereof respectively correspond to the individual file items in said file system.
4. The method according to claim 1 , wherein in response to an operation performed by a user that creates a file item, a corresponding node is created on said file system energy tree, and said created node is assigned to have an energy score equal to that of its father node.