1. A method comprising: under control of one or more processors configured with executable instructions: storing a semantic keyword in a text filtering system, the semantic keyword comprising at least a basic keyword and a logical operator; finding the basic keyword of the semantic keyword in an input text, the finding comprising: obtaining a character c 1 in the input text; using 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; determining 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, setting a next character following or preceding the current character to be the current character, setting the child node to be the current node and repeating 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, setting the sibling node to be the current node and repeating the determining of whether the current character matches the current node; 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 the current node and the current node does not have a sibling node, connecting the last matched current node to the root node to obtain a matching route; and determining 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; in response to finding a text content matching the basic keyword in the input text, conducting 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 in an event that the semantic match is successful, filtering a matched text context.