| With the explosion of Internet, how to get the piece of information what he want from the web has become a serious problem, so information extraction from web pages is necessary. With different application and information sources, the method of extraction information is different with each other too. The topic Web pages and data leading type Web pages are tow type of information sources in Web application at present.As to the topic Web pages, this paper presents a method of information extraction by pruning the nodes of which information entropy production reach a certain extent. Firstly, a DOM tree is constructed by parsing HTML document. Then, the nodes which don't need to be dealt with are filtrated out, and a STU tree is created. Lastly, the nodes whose information entropy's increase overtops the threshold value are pruned, and the topic information of the Web pages is obtained. The primary experiment result proves the validity of the method using for extracting Web page's information.As to the data leading type Web pages, this paper apply standard technologies of XML to web extraction problem and developed a platform of web information extraction based XML. With Inductive Learning arithmetic lactated and identified the information blocks that we want. This paper used standard XSLT and Xpath, exploiting their powers of data location and conversion, to solve the key problem: writing extraction rules. |
