1. A method for text classification comprising: segmenting content of a text into multiple words; determining a sum of a plurality of word vectors of the multiple words at a first level vector space of a vector space group that includes a plurality of vector spaces, at least one of the plurality of vector spaces comprising one or more direct child classes that are non-leaf child classes in a tree class structure, the first level vector space having a plurality of classes; and classifying the text into a class of the plurality of classes that has a shortest distance to the sum of the word vectors.