Nutch always crawls from from a parsed file to the urls contained in the file. However, if we want to crawl a specific type of files (e.g. rss file), there may be some difficulties. As the links to real rss files are always contained in some entry files of html/htm, so there is no direct urls from one rss file to another. If we want to index rss files, we have to index many html/htm files first.
-- 《盖世豪侠》好评如潮，让无线收视居高不下，无线高兴之余，仍未重用。周星驰岂是池中物，喜剧天分既然崭露，当然不甘心受冷落，于是转投电影界，在大银幕上一展风采。无线既得千里马，又失千里马，当然后悔莫及。
