7. The system as recited in claim 5 , wherein: the semantic keyword comprises a filtering condition; and the semantic matching unit comprises a category matching sub-unit that matches an attribute of the input text with the filtering condition.
5. A text filtering system comprising: one or more processors; memory; a keyword storage unit stored in the memory and executable by the one or more processors that stores a plurality of semantic keywords; a basic finding unit stored in the memory and executable by the one or more processors that finds a basic keyword of a semantic keyword in an input text; a semantic matching unit stored in the memory and executable by the one or more processors that, in an event that a text content matching the basic keyword in the input text is found, conducts a semantic match in the found text content, the semantic match comprising matching the found text content with the semantic keyword according to the logical operator included in the semantic keyword; and a filter processing unit stored in the memory and executable by the one or more processors that, in an event that the semantic match is successful, filters a matched text context, wherein the basic finding unit comprises: a text obtaining sub-unit that obtains a character c 1 in the input text; a character matching sub-unit that: uses c 1 as a current character and a root node of a tree-type structure as a current node, the root node corresponding to one of a first character or a last character of the basic keyword, determines whether the current character matches the current node, in an event that the current character matches the current node and the current node has a child node, sets a next character following or preceding the current character to be the current character, sets the child node to be the current node and repeats the determining of whether the current character matches the current node, in an event that the current character does not match the current node and the current node has a sibling node, sets the sibling node to be the current node and repeats the determining of whether the current character matches the current node, and in an event that the current character matches the current node and the current node does not have a child node or the current character does not match with the current node and the current node does not have a sibling node; and a determination sub-unit that: connects the last matched current node to the root node to obtain a matching route, and determines whether the basic keyword is found in the input text based at least in part on whether the matching route includes a successfully matched leaf node of the tree-type structure.