<dependency>
    <groupId>cn.edu.hfut.dmic.webcollector</groupId>
    <artifactId>WebCollector</artifactId>
    <version>1.42</version>
</dependency>

public class ZhihuCrawler extends BreadthCrawler{

    /**
     * This function is called when a page is fetched and
     * ready to be processed by your program.       
    */
    @Override
    public void visit(Page page) {
        String question_regex="^http://www.zhihu.com/question/[0-9]+";         
        if(Pattern.matches(question_regex, page.getUrl())){              
            System.out.println("processing "+page.getUrl());

            /*extract title of the page*/
            String title=page.getDoc().title();
            System.out.println(title);

            /*extract the content of question*/
            String question=page.getDoc().select("div[id=zh-question-detail]").text();
            System.out.println(question);
         
        }
    }

    /**
     * start crawling
    */
    public static void main(String[] args) throws IOException{  
        ZhihuCrawler crawler=new ZhihuCrawler();
        crawler.addSeed("http://www.zhihu.com/question/21003086");
        crawler.addRegex("http://www.zhihu.com/.*");
        /*start the crawler with depth=5*/
        crawler.start(5);  
    }


}