网页爬虫(也被称做蚂蚁或者蜘蛛)是一个自动抓取万维网中网页数据的程序.网页爬虫一般都是用于抓取大量的网页,为日后搜索引擎处理服务的.抓取的网页由一些专门的程序来建立索引(如:Lucene,DotLucene),加快搜索的速度.爬虫也可以作为链接检查器或者HTML代码校验器来提供一些服务.比较新的一种用法是用来检查E-mail地址,用来防止Trackback spam.-A web crawler (also known as a web spider or ant) is a program, which browses the World Wide Web in a methodical, automated manner. Web crawlers are mainly used to create a copy of all the visited pages for later processing by a search engine, that will index the downloaded pages to provide fast searches. Crawlers can also be used for automating maintenance tasks on a web site, such as checking links, or validating HTML code. Also, crawlers can be used to gather specific types of information from Web pages, such as harvesting e-mail addresses (usually for spam).